Why is my crush acting this way?

well, to be honest she may be shy to show you her feelings, what i suggest is try to talk to her, yeah she may not wanna talk to you but thats the only way. maybe try to write her a note and slide it into her locker, be sweet and be honest. tell her your true feelings towrad her and tell her how is makes you feel whever she is mean to you. if none of that works, i may suggest moving on. if she is shy like you mentioned she may be shy around you. you know what they say, when someone bullys you and is mean to you that normally means they like you. hope this works. good luck!