Why did she suddenly start avoiding me?

Hey so there is this girl at work and im new over there. From the start she was showing me a lot of interest and being extra nice to me. Plus i caught her looking at me and getting restless and nervous too especially if i wasn't giving her attention. But its not like i would never talk to her. i did entertain her and make conversation a bit. One day we she was talking to me quite well and being friends but then all of a sudden the next day she was avoiding me for the whole shift and would get nervous if we ran into/ walked across each other putting her head down. Although she was wearing a cut out top revealing her tummy and pierced navel and funny thing is at the end of the shift when i was going to clock out she suddenly was blushing at me and waved good bye and when i had a doubt about my cock in card as she's part of the admin staff she was being very friendly in informing me. (she did have her tummy covered with a hoodie she was wearing if that makes any sense) what was the meaning of all of that?

Sounds like she got cold feet about getting too friendly with a coworker.

Maybe she has a crush on you but doesn't want to start anything at work.

Sounds like she masturbated to you and now she is ashamed to look at you knowing what she did. I have seen dumb girls do it all the time. Or some rumor about you reached her ear. I bet it's the first though.

You say she is part of Admin Staff? Does your company have a policy against Admin staff dating employees?