Flirting? Always wants my attention?

She's always trying to get my attention especially when im around my friends. (the time that don't rlly pay attention to anyone other then the person im talking to) If im in Homeroom she takes my friends seat when he go to library, different class, etc. She even abandoned her friends at lunch to sit with me and kids she doesn't know and she doesn't talk to them at all. Wtf is she doing?? Its kinda awkward but i rlly haven't said anything cause i rlly don't care about it much. Any answers will do........ Shanks XD