She's flirting with me?

This girl at my job, shes pretty nice to make a long story short got to talking with her a bit and she works at a local restaurant and so I told her i will have to stop by since I hate eating the same stuff each day for lunch and told her I hope she can tell me what's good and so on.. so she agreed to that, anyways got to talking about my past failed relationships where I got burned and she was telling me how I was sending the wrong flowers and what not, she told me her favorite flowers so I noted that.. so on my way to work I told her I was sorry if I scared her because I saw her at the last min, and she asked me "did you see that ass shaking?" and I just chuckled, later on in the day she was telling me she can cook and so I made a joke saying maybe you can make a birthday meal for me since my birthday this year falls on Thanksgiving and she gave one of those girly chuckles.

Now here is the part that confuses me.. she has this thing she does, like say I flirt with her, like one day she said she was hot or something like that, and I said I was hot but empathized that I was hot and she laughed and she always rubs her stomach under her shirt like anything you make a flirty remark, always facing towards me.. I told my male friend to watch and I did another and she did the same..

I never seen a girl do that but maybe I just never noticed?