The Waiter

Okay so I need some advice. A week ago I went out to eat randomly with my friend & my mom. When I went in the waiter looked at me I mean like I was looking beautiful that night compared to other days and he kind of smiled to himself. So we sat down at the table and he started to flirt with my mom and kept side eyeing me. He made me laugh. I'm asking for advice because I'm not sure if it was to get a tip or if he was just doing his job. But he did pull my friend to the side when she got up to use the restroom and he asked her about me like how old I was he said I was cute which I could understand because he didn't want to come off desperate and he asked her if I was her sister. When we left he made SURE he opened the door bc he was at the back while we were at the front. He sprinted to open the door. Should I go back? Should I advance to talk to him and get to know him and get the number? Was he really interested? I'm thinking on going back hopefully he's there. I haven't got him off my mind since.