How do I know that she knows that I like her?

Sometimes if the girl is shy, she might either get defensive( say something kind of mean) or totally quiet like not knowing what to say. She might try to avoid you because she likes you, she just doesn't know what to say. Go up to her and try a conversation. Even if it's awkward, still pursue her until she's comfortable. If she isn't comfortable after a while, and you still like her, you could try texting her and calling her.

Well it depends. Cause if she doesn't like you. She is gonna try to avoid you or she might get away from you. But if she does like you she probably get nerves. Or she might blush a lot when you make a complement to her. Also she might look at you a lot. You know its all in the movement and words. Well I hope that I could help. Good luck.