Why did she look at me, then look away?

Okay, in lunch, 2 days this week, my friend Daryl sat me with me in lunch. This girl sits in the table diagonally across from mine.
I showed my friend Daryl a song on my iPhone 4S, and I could tell that this girl was staring in my direction… I looked up at her… She looked away. We made eye contact for a brief second both times. I think she did this again yesterday too.

She's a freshman and Daryl and I are juniors.

This girl sat in a group with guys… But so does my other friend and she has a boyfriend

If her body was facing towards yours and looked away when you looked back then she has an interest

Look again for second and third time, If she look with same point she interested in yours.