There's this girl but I don't know her?

Okay so I just started working at a restaurant that my uncle owns in Ohio and there was this really cute girl that came in and I wanted to talk to her and stuff but I never been in a relationship and she was a few years older so pls help me and give me tips for if I see her again ohh and I'm just a cash register man and I'm super shy and she's different cause I've seen her before and I feel sorta weird in my stomach when shes near and I don't usually feel this for other cute girls so please help