no one can say for sure what her actions mean except her. Everyone can speculate til the cows come home but none of these analyses will likely be accurate.

Now on the surface her looking at you in the manner that you said, does not speak to what someone else said as thinking you're creepy. I don't think she'd be looking at you in that casual and somewhat friendly way if she thought that. But one cannot say for sure if she's interested or not.

Say hi when you have a chance. nothing will tell you more than if you try to interact with her. no risk in that as you're not asking her out, but you can gain some insight by seeing how she responds!