I'm guessing you have asked her out and she might have said no for some reason. The thing is do you Love her or do you just have a big crush on her? If you love her, then you might not ever get over her. But if it's a crush then it comes and goes. If you truly want to get over her, my best advice is to focus on her negative things. Look for things that you don't like about her, of course it's hard when you really like someone, but focusing on the bad things will make you like her less and less.
I would say there is reason to get mad at youself, means if she is not interested then u gotta move on i know this is hard lesson to learn but believe me i have learned it and exercising everyday, so be just friend with her like any other classmates in the next 2 years and if she start changing then take a chance and win the game.