Does a 12-year-old girl like you if she is always staring at you and flirting and she's mad because you don't talk to her but she told you to stay away and that's all you were doing?
More then likely yes. This sounds like you are an elementary student. This is a time when young people start to notice the opposite sex, but are shy, lack wisdom and understanding and are unsure of their feelings. She probably does like you, but she did give you a warning "stay away." I would listen to that warning and when you see her just smile at her until she gets more comfortable with you. When and if she does then you can become friends and perhaps even go out to a movie together. Generations of kids never change. When I was in Grade 8 there was a red-headed boy who would poke fun at me all the time and even give me an old "happy slap" on the back every so often and I ended up punching him square in the nose! LOL I didn't realize, because I was so young, that he liked me and I sure did hurt his feelings.