First and only love of my life

I'm 15, I met this girl in 3rd grade when I was 8 years old. She was my first crush and I've always liked her, there was something special about her .. We went to middle school together, but not in the same class, just the same school. In 6th grade we didn't talk, but in 7th grade we started talking on Facebook and in April 2011 I told her I loved her, and she said she didn't love me. She hooked up with 2 guys the time I was suffering and said she was sorry that she didn't love me. We kept being friends until October when I decided to cut every contact with her and didn't talk to her until February, when she texts me and says she loves me and we should see each other. I was very happy about it, so I gave her a shot, we went out and I asked her to be my girlfriend and she said yes. We've been together until May 2012 then I broke up with her. I still don't know the reason, I think it's because I felt like she felt ashamed to be with me, and didn't really care about me, she used to tell me "I love you" but she didn't show any feelings towards me except some kisses .. (no we haven't had sex). So anyway, she said she cried for me and said she wanted to be with me but I decided not to get back with her so we stayed friends and sometimes we used to hangout. Last time we hangout was in February 2013. After that, I blocked her on Facebook again because I felt like I wanted to be with her again and I was very scared and we didn't talk anymore. On Easter (April 1st) she texted me saying "Happy easter I miss you <3" and 5 days later she texted me again saying "You were a douche with me you disrespected me. Goodbye." So I asked some people why she did this only 5 days after she said she misses me and they said she has a new boyfriend. So after 3 weeks on May 1st I unblocked her on Facebook and said I'm sorry and I still had feelings for her and I wanted to get back with her but she said she prefers her new boyfriend, and she will only be with me if he leaves her and says she won't leave him cause she likes him. I did the WORST mistake and I tried to talk to her boyfriend trying to ruin their relationship, cause a friend told me that it worked for him, and after she found out she blocked me on Facebook and said she hates me because of it. She said she tought about getting back with me and still had feelings for me but after this mistake she will always hate me. I tried to go to her house and brought her flowers and she didn'accept them, and when I see her on the street she checks me out but doesn't even say hi. I know I f*cked it up but I don't understand why she didn't want to leave her boyfriend that's been with her for only 3 weeks (and she said she doesn't love him) and get back with her first and only love (that's what she told me). I mean, if I was with somebody else and the person that I still have feelings for and loved very much comes back to me, I'll get back with her, no doubts about it.So now I don't know what to do, some people say I should ignore her and try to make her jealous so when I stop contacting her she'll miss me, like she did 2 years ago, others say I should keep trying to apologize and show her that I care but her ex boyfriend (the boyfriend she had before me) tried to get back with her but she said no. (but she didn't love him) So now I don't know what to do, I'm very confused I mean, I know I was a **** but if you love someone you don't hate them for one mistake ..love is more powerful ..and also you would get back with the person that you loved instead of being in a 3 week relationship with this new guy .. I tried to talk to some of my female friends that know her and they said she'll miss me in time and she'll get back with me but her best friends blocked me on Facebook too and won't talk to me .. I only talked to her sister that say she'll get back with me but right now I should leave her alone.
Please, don't tell me to move on, I know I did a lot of mistakes, but I really believe in our love, we really had something special, we were friends, lovers, we suffered for each other, and in 7 years we've always tought about each other (she always sent me happy birthday / happy christmas texts). I don't seem to understand how her feelings changed in a month and now she suddenly hates me for that mistake ..I mean, she says she doesn't love him so it's not love, and if she loved me, she couldn't say she wanted to get back with me ONLY if he left her, and keep me as a second option .. I think she loved me because other guys tried to be with her while she was suffering for me, always contacted me, even gave me her Facebook password and said I could check her account if I wanted cause I'm the only man she wanted to be with, and I don't understand why she changed her mind so quickly, she said she misses me on April 1st, then she says goodbye on April 5th, on May she said she tought she was getting over me but she still had feelings for me but still prefers her new boyfriend.. my mom simply says that hate and love are similar and she hates me cause I made her suffer but still loves me cause love doesn't disappear that quickly and she's just scared of being hurt again .. please, what should I do ?
She's acting a little bitchy right now because I gave her a second chance after she treated me like s#it and hooked up with other guys 2 years ago (nothing lasted more than a month) but I loved her so I gave her a second chance but she doesn't want to give me a second chance right now ..
Also, I don't seem to understand why she didn't want me when I was a nice guy but wanted me when I was a douche and didn't talk to her for 6 months, and still wanted me after I broke up with her .. I mean, she wanted me when I was a douche .. but she said she fell in love with the good side of me but it seems that when I treat her right she pushes me away ..So what can I do to get her back ? I don't believe shen she says she hates me because shen she said "Goodbye forever" and I came back she didn't reject me ..but now she's using big words like "I hate you. I'll never get back with you. It's over forever". I hope she's just mad at me, I know I didn't have to try to ruin their relationship but is this such a big mistake ? Some people get back after someone cheated or even agressed the other person .. I never did those things but she makes it sound like I'm the biggest douche ever ..

Awh, honey, I know it feels like the end of the world. Trust me, I know the feeling. But you are SO young. The chances of you two being together forever are so rare. But you know what that means? Maybe you don't believe it now, but theres someone out there who is better for you, will make you happier and treat you better. Relationships are almost impossible at you're age. Teenagers are so hormonal, their changing so quickly. Teenage years are very hard, I know. Think about it for a minute; youre 15. Youre so young. You have so many people to meet, so many things to do. You should be happy, not dealing with this. She doesn't know what she wants, its obvious. I would get out of it and move on if I were you.

Thank you, I know a lot of people are immature at this age, me included, but you know I only wanted her for like a year and she didn't, a year later she says she loves me and even though I broke up with her she still wanted me for the last 8 months so she didn't jump from man to man ..but now seems she changed her mind in one day just because I tried to ruin her relationship and made her so mad .. I know it's bad but I'm not sure it's worth to lose a love for such a mistake ..

I understand. You do seem mature for youre age. Funny thing is I was in almost the exact same position when I was youre age. It was when I was 15, turning 16. I understand completely where she is coming from, trying to ruin a relationship is gonna make her mad and ultimately make the situation much much worse. But I get that revenge feeling completely. Really all you can do for now is just break off all contact. One of two things will happen. One, you will get over her and move on and be happy without her. Or two, shes gonna realize youre gone and realize you dont want to worry about her BS anymore, and come crawling back to you. Maybe by then youll be over her, too. Just stay strong. Everythings gonna work out in the end.

You are right but the thing that scares me most is that is the second time in my life when I suffer for this girl, and other guys tried to tell her like "I'm gonna be better for you stop being hurt by him" (when I was ignoring her and she loved me) but still, she prefered me and pushed those guys away ..I was the only exception who told her "i love you" (5 guys said that to her, she's quite amazing for some reason) and she came back to me only, and now I'm also hurt by the fact that she might forget about me like she did with those other guys ..plus, I don't understand how she told me the day I talked to her in May "You are the most important person in my life and I care about you but I prefer my new boyfriend, I won't leave him" I mean, why would you prefer someone that you care less ? And the next day after she found out I talked to her boyfriend and try to ruin their relationship, she started saying "I hate you. I'll never get back with you. It's over forever". She changed her mind so quickly in just one day, and I don't know if it's her pride, or this guy made her fall in love at first sight ..cause someone who loved you for over a year and says you are the most important person in her life doesn't prefer being with a guy that you've been with for only 3 weeks and keep your "first and only love" (that's what she told me) as a second option (she said she'll be with me after he breaks up with her, cause she doesn't want to leave him). I mean, it seems like she didn't even care about their relationship but still kept me as a second option ..damn I'm so confused.