Can't stop thinking about this.

TLDR at the bottom.
At the end I've got what makes me think about this still, the middle is the story that goes with it.

She just wants to be friends. But there's a long story that goes along with this, and some texts. Feel free to ask for clarification, I'll try to explain anything to the best of my ability haha. (Each seperate quotation represents a different text)

About a week before I realized that I liked this girl, I just got over another girl who just wanted to be friends.

So I got her number and texted her, it seemed like she was flirting. I commented how I was going to go eat some rice and how maybe next time we could actually have a conversation instead of just random stuff, and here was her response "Oh that's awesome! And I know I suck at texting dude. I'm probably one of the most boring texters you'll come across". It seems flirty to me, even with the "dude". Then I said "Even if you're a boring texter ur still an interesting person :b". Here was her response "Awwh yeah! I'm interesting! Yay hahaha sorry that I didn't answer, I was falling asleep. And yes, I do fall asleep at 9:30 due to my lack of sleep yesterday and plus cross country just tires me out".

About a week later after debating whether or not I should get to know her more, I decide to go for it. We would be going to six flags soon, so I could be a little flirty via text until then, and then talk with her some more at six flags. I asked her if she would go on a ride at six flags with me when we go, and she agreed. Later on I say "Im off to bed, ttyl gurl. Goodnight" and she replies "Night!!"

I text her a couple days later, and eventually bring up six flags. I'm gonna give you our conversation word for word for this part, there's a lot, bear with me please. Here's the conversation

Her: "Hahaha alrighty then.. I dont even think im going to six flags anywho. And are you good at running?"
Me: "Aww, now ive got no one to go on the giant drop with me :( why not though?"
Her: "I'm busy and stuff.. Hahahaha"
Me: "Busy? Too busy for six flags!? Impossible. Whats more important than fright fest?" "Anyways, you should totes go." "only if you become un-busy of course ;p"
Her: "Everything is more important. And nahh"
Me: "Nothing is more important. I respect your decision to not have a blast at six flags with us though, even if its a lame decision." "But what are you doing instead?"
Her: "I said I'm busy. THATS ALL YOU HAVE TO KNOW. hahaha" <<<<< Last text she sent to me
Me: "Alright, alright..."
---So I'm thinking that we don't even know when were going yet, so how could she know she's busy? I thought maybe she doesn't want to go because of me for some reason, which is why she won't give me a specific reason as to why she isn't going all of a sudden.

Here's where I go wrong. I'm friends with her older sister so I text her.
Me:"Hey, is your sister not going to six flags with us cuz of me? I dont like beating around the bush, so if she doesnt like me or something, id like to know. Its already kinda weird asking u like this, but itd be weirder to ask her. Thanks" "God damn I feel like a creep after asking that."
Her sister: "No?... why wouln't she go because of you, she barely knows you"
Me: "I asked her why she wasn't going, and she said she was busy, thats alli need to know. Since she wouldnt tell me y she wouldnt go, I just assumed she didnt wanna go cuz of me, and just didnt wanna say it. I got paranoid, sorry." "Im off to bed, goodnight" "I already made a fool of myself, so I might as well get this off my chest: I kinda like your sister, and I get 'paranoid' if i dont think they like me back"
She never responded, but the next day when I said hi to her older sister, she said we needed to talk. It eventually lead to her telling me that her sister just wanted to be friends.

That's what happened, thanks if you read it all.

Now here's what's making me not be able to stop think about this: I'm a senior in highschool, and she's a freshman in highschool; but she's cute, has a really nice smile, and laughs a lot. I hungout with her older sister once, and she hungout with us, I couldn't stop looking at her, and everytime I looked at her, she was either laughing or smiling. We barely knew each other, which makes me think she found me unattractive or something. This freshman makes the last girl that turned me down seem so damn boring, and like I said, we barely knew each other. I'm almost positive she's never been in a relationship, so could she just not want this because of the age difference?

Also, I know there's plenty of fish in the sea, and I'm pretty sure I have other options, but at the moment I'm not interested in those other options.



TLDR;
I like this girl, she's a freshman in highschool and I'm a senior in highschool. I approached her older sister about liking her and her older sister said we should just be friends. I'm very attracted to her, even if she is just a freshman. I talked to her a little about this, and now I can still talk to her and see her without things being awkward. First thing that comes to my mind is that I never even got to know her before being "turned down", maybe that's what's making me want her more?

Thoughts?