Does she like me i dont know if she does?

okay there is dis girl she asked me out once n i said no den a year later i thought she stoped liking but now in cl i sit behind her she turns around n talks to me and she is always laughing when she look at me and smiling so one day she ask if i got a phone n all the sudden she puts her number in and she is always happy when she sees me and i started really liking her but the problem is she thinks i dont lke her so now she barely says anything i dont know wat to should i ask her out cuz i really liker her now i dont now how to tell her i like her she is always with her freinds helppp pleasee