She just might like you! from experience I know that if she is shy she wouldn't want to look you straight in the eyes if you are looking at her.. And its almost like a tag game with her eyes she wants to see if you are looking at her and when you notice that she is looking at you she kind of looks for a couple of seconds and turns her head or just stops looking at you!
well when she is looking your way and gets nervous it means that either she thinks your cute or she likes you but she gets nervous thinking that you think she likes you even tho she does but she doesn't want to make it obvious because she might be scared that you might tell her something
She really likes you. When you look at her, even though she likes it, she gets nervous and doesn't know what to do. She doesn't want to look stupid by continuing to stare at you or something along those lines. So her first instinct is to look away.
oh she definitely likes you! her expression either wouldn't have changed or if she was in a bad mood she would glare even more at you. most of the time if a girl looks at you or locks eyes with you, especially more than once, she likes you...unless you're just a weird looking dude or something. trust me, you guys aren't interesting enough to look at or even notice unless we find you attractive or like you. girls can stare at other girls for the hell of it, we're comparing our looks to theirs, we like their shoes and so on. for the most part you guys all look the same so unless we like you or find you exceptionally attractive there's not much to catch our attention. go talk to her and ask her out.