I was walking with my friend to class & I saw the girl I like there & I was looking her but then I just looked away. But then later we pass by again at the hallway & I turn around to look at her but she hide behind her friend. Then later when she came to class I was looking at her & she caught me looking so I just looked away. Then when she went over to talk to her friend I was looking at her but then I stopped. But later when I turn around I saw her at the back of the class & she was looking at me but then later she left class early?

Oh for pity's sake, how old are you? We have no idea how much 'looking' is too much and whether or not she dislikes you.
Staring is very very common in the early and middle teens. By your late teens, you should be able to figure out the steps to get to know someone - days of unforced smiles, maybe a hi here and there, in passing. Then more hi's and smiles more often, with a little pause as you walk by, or turn around and smile again. Finally a little comment on the day or the class or even 'how are you?' If she isn't responding in a friendly way - she doesn't want to get to know you more.

I'm guessing you're 9, 10 years old?

You looked at her, she looked at you, you looked at her and she wasn't looking at you, then you looked at her and she was looking at you, then she left class early probably because she had another class to get to, but because you keep looking at her and she sometimes isn't looking at you when you look at her, you don't know what to think?

How about asking her! You know, open mouth, make words, say things like, "hey I like you, that's why I'm always looking at you. Do you like me too?"

I need an aspirin!

I have two teenagers, 13 and 17, almost 14 and 18. Thankfully both of them are smart enough, and brave enough, to talk to the people they like, instead of staring and hoping to pass on the fact that they like someone, through telepathy!

Yes, you know and look on purpose, so it is too much if the other person does not want to be looked at.

Who knows. Have you ever tried talking to her?