Could this girl be interested?

So last Saturday, a friend invited me for dinner at a restaurant (TGI Fridays and if you don't know it, it's like Applebees, so as to get the setting). We are not any kind of buddies but we have a good relationship. When I went there, there were 5 other people, among which a guy from my class with 2 girls. I found one of them to be very attractive, but I am kinda relaxed this period and I don't 'hunt' for girls, so I didn't try flirting her. But of course, eye contact was unnavoidable as she was sitting on the other table, opposite of me.(Now I'm not trying to say I wouldn't like a relationship, don't get me wrong, I'm just more passive on the subject at this time and let it come naturally, and if it comes, I respond.) After a while, the girl with her friend came on our table, still being opposite of me. We were telling jokes at the moment, and I didn't make a try to talk to her on purpose so as to test the waters. I was surprised to see that she actually started talking to me, she introduced herself and started asking stuff like what I wanted to study. Then again, a similar question, generally, she looked like she wanted to chat. When she asked if anyone had facebook, I told her I did and that I'd add her. After that, we had a small talk, I said a couple of funny things, she laughed, and so on, but still on a calm base. When time came for her to go, the host asked her to stay a little bit more, but she said she had to study, so I jokingly told her to tell me her lesson by heart at which she laughed very much. Then came this. I shall point out it was the first time I saw her :) : she went and kissed me (cheeks of course)and just did it like she knew me, and then said 'you and me will talk in facebook!'.

So...what do you think? Could she like me or is she just being friendly?