This is a hopeless (and pathetic) situation what should I do?

I like this girl a lot, we are both 17. I don't know why I like her so much because i don't even know her well. She has a boyfriend right now ( a dude she dated last summer), and I'm going to Arizona for college and or hs is in nj, so it doesn't make any sense for me to go after her. So like I'm conflicted becuase I like her, but its hard to forget about her because i see her everyday and she is so pretty. And earlier this year when she was single we started to flirt and talk a little, and we always made a lot of eye contact, but she was quiet and shy, and so am i. So she was kind of giving me mixed signals and i just did nothing, mainly becuase im stupid and clueless. And now i notice her in more places I am. And in class now she is still quiet but now will be load randomly, and she didn't do that earlier in the year, and then she looks around to see who heard her. A week ago, the girl who sits next to me was absent, so she moved to that desk next to me, for no real apparent reason, because she could still talk to her friends and stuff in her normal seat and whenever id say stuff to the teacher sometimes shed be like "YEAH" in agreement but I just ignored her, and then yesterday we had a test and i didn't get some stuff on the review packet so i asked my buddy and he said he didnt know then immediately she shouted I DID THE PACKET like not to anyone in particular but Idk she might have wanted me ti ask her, but I didn't becuase im just confused and i dont know if i should go for her or forget about her (which is the option that makes more sense). And she will sometimes just randomly answer a question i ask to the teacher or something. And a couple days ago i got into a little fight (the other kid started it), and she saw it so I was a little worried she would think less of me but she didn't seem to. But i dont know what all this means and stuff, and it just feels like such a lose-lose situation