What is this girl doing. I need some advice please?

I am at Charlotte Motor Speedway in the infield. I met a girl who is very pretty and I like her. She is 15 and I am 17. We started talking here and we get along really good. We are kind of play flirting. The main thing is she is making it known she has a boyfriend constantly. So she acts like she is into me, but yet constantly brings up her boyfriend. What does it mean???