Is this girl interested in me?

So, this girl i know ALWAYS seems to notice if I ever had something on and don't have it on the next time she sees me or if I even glance towards her, she asks me why I'm looking at her. Even though, she can never seem to look me straight in the eyes for more than less than a second. She'll just look at me, look to the left, look back, look to the right, look back and either turn around and walk away or just turn around in general. Anyway Why she watching me like a hawk? Help me please? :)