I like this girl and I don't know if she likes me.?

This girl lives in Penn. and me in Del. Shes only a grade higher in highschool than me. She comes with her fam. to meet my family and our friends family sometimes. She smiles at me, makes eye contact with me, and she laughs at alot that I say. Still, i'm not sure because shes a nice girl and i don't know ifshe only shows me these signs. How can I find out, and would it be a good idea to go out with her even though shes in Pen. and im in Del? We watched a movie and we were on a couch with a few other people. I dont know if she leaned in but she wasn't nervous. She didn't ask me to scoot over even though i could of moved over about half a foot. When I talks she listens and alotof times has small laughs. When we were in the mall with a few others and me and her were waiting for someone, she said wait here, went off in the store we were in, and came back in a minute.???.