In a sort of love triangle right now. Need advice

So, I'm only in highschool right now, but it's my senior year, and I turn 18 in about a month. Right now I'm in kind of an awkward situation, sorry, but this is going to be a bit of a long post if you don't mind reading alot.

I just joined a youth group starting the end of last year, and there's this girl that's in the group, and I honest to god am sure I love her. I had known her from freshman / sophomore year, we hung out, did alot of stuff together, and I mean it's not like dating her never crossed my mind, but I was already dating this one girl for a few months. Well Junior year she had to move a short distance, but just enough that she got moved to a different highschool. Now I'm not dating that girl I mentioned anymore, and we've started hanging out again since I joined the youth group, and I honestly feel like she's the only one for me. But we can't simply be together now, because she's been dating a guy for about 7 or 8 months.

I just need some advice, I don't know what to do. I feel like I truly love her, and the thing that's so special is it's not about sex, or how hot she is, I love her for who she is as a person. But now I mean, I don't want to be that douchebag that attempts to ruin a person's relationship, but honestly I feel like if I don't do something soon, she'll be off to some college, I'll be off to a different college, and we may never see each other again for all I know.

She will be off to college.....it's a given you will be wasting your time...lots of horny guys there for her to choose from.

Tell her how you feel...don't worry about the other guy. Always be upfront and tell people how you feel. She would like to know trust me....even if nothing more comes of it. You will feel better for getting it off your chest too. She will be going off to college though, and very few relationships survive college. You will want to be single in college too.

Let her know how you feel. That is all you can do. No matter what happens, I guarantee you will feel better for giving it that effort. If she turns you down it may take some time to feel good about the effort but you will eventually. It feels good to know we have been brave and we made an effort to get what we want. There are many situations in life where we have to risk a little in order to get a major reward. If nothing else, this is an exercise in being brave.

Most likely it isn't going to work out, but be brave and start taking charge of your life. If it doesn't work out, remember that she wasn't the one for you.

I know exactly how you feel with the whole feeling like a douchebag thing about ending someone elses relationship. I'm kinda in the same boat now, my stories kinda pointless lol. But basically get this, this is what my friend told me: you're in highschool, relationships almost never last in highschool, if you're ever gonna have a time in your life to live it's now. Do what makes you happy, and stop giving a **** about what anyone else thinks or says, don't worry about being the ass. Do it for you, cause I can almost guarantee that if he were in your shoes he wouldn't give a **** if you're dating her or not. It's highschool dude, you're not ****ing up a marriage. How's there relationship even? Strong? Barely holding on?

Listen to what you said even "...I honest to god am sure I love her."
You've got one highschool term, and one life my friend. Live it up. Mistakes and success comes and goes, but regret is a life time.

She's going away to college regardless, you might never hear from her again if you don't speak up, trust me knowing that you tried, is better then wishing you tried!