Girls, Why she keep smiling to herself?

[Anonymous]

A girl who works at my university library, she is relatively young. Early twenty’s, I have noticed that whenever I’m around , she will often glance at me and smile to herself in a coy kind of way.
I dress normally , I’m just minding my own business, however a while ago I did kind of check her out and got caught. But this was months ago. But I still notice if I’m around and talking to people she will often glance at me and if I look back she kind of smiles to herself

[Jdssksk]

I also do something similar around a guy I like. I just get flustered when I see him and I can't help but smile. Maybe have a friend sit around her or something and see if she does this with other people