Whats wrong with this girl.?

There is this really hot girl that works at the gym. I've seen her look at me few times. I just don't get one thing. She works at the front desk and says hi to all the people that check in. Every time she sees me walk in the gym and i go check in by the desk that she works at she will quickly turn away or walk away from the desk. I never met her before so i don't know why she is acting like that. I don't think she does it to any body else. Why she keeps looking at me at the gym but will walk away or turn away when i get close. One of my friends says that she checks me out at the gym. I've seen some dudes talk to her at the gym and she doesn't seem to be shy. All the people that work at the front desk always say how is it going to me or just they just say hi but she is the only one that never said anything to me.