Does she like me or is she just interested?

Ok, I really like this girl in my cl and believe shes interested in me. Alright this past week I had asked her for her number and she gave it to me, she then asked me for mine (don't know if this means anything) and so since then I have been talking to her... But this week when I was talking to her I had asked her to come sit next to me.. she did and when we started talking to me she would twirl her hair and when I would talk to her she would look around as if she were nervous. Today at lunch she sat next to me as she always does and we talked once more... but again she kept looking back and fourth. I do want to mention that when we talk its a quick conversation and then its dead.. Today our conversation was actually more complex. I do notice that she tends to look at me and then turns away quickly when i look at her. I would also like to add that she is shy. But surprisingly enough she waves at me and says hi everytime i see her. Can anyone tell me if she likes me? Where I am at? What I should do? Any suggestions at all?