Does she like me or not?

ok so there is a girl at my school that i have liked for a while. So every friday night after the football game me and my friends(some r girls. so she isnt the only one) go out and eat. so the last 2 weeks i asked her to join us and she has. And she sits next to me and laughs at everything i say and acts like she is having a good time. but tonight was the sadyhawkens dance for my school and i felt like she was avoiding me the whole time. And when ever she is with her friends she rarely even talks to me it fells like. i really dont know if she likes me or not any signs i should look for?