Is this younger girl interested in me or scared of me?

I have a crush on a girl at work who's younger than me- I'm 29 and she's 20. Over the past few weeks we've gotten to know each other a little better, but wouldn't say we know one another that well. We don't work alongside one another, so it can be hard to get a chance to talk to her. If I pass her in the hallway, she looks into my eye and says hiya.

Anyway, whenever I approach her to talk to her, she kinda talks in a kinda playful but shy way. Like being sarcastic about enjoying work, something like that. She always says when she's off work she's going to get drunk, but it's like a kinda generic answer when she says this. When I'm near her, she finds it hard to make eye contact too. We do talk about silly things, but she is kinda awkward and seems to not look at me much or let her guard down too much.
Anyway my question is, is she afraid of me? Is she shy of me? Or does she have a crush on me? I think it might be a mix of all of those, but I can't tell if she's intimidated by me or if she has a crush and is just shy and trying to be cool and not mess up around me. Any idea?