It sounds like she is trying to get your attention for whatever reason. You won't know anything until you actually go for it and talk to her. Good luck :)
There is this girl who stares at me during class sometimes. I sit to the side of her and she turns the other way and plays with her hair. She treats me differently. Does this mean she likes me?
Maybe, maybe not. Us girls can be really complicated. Just try and befriend her and see what happens.
Break the ice with a joke, compliment, or question first.