Is this girl attracted to me or is there another reason for this?

This girl used to hate my jokes, was irritated by everything I said and generally seemed to detest me, but during that time she also added me on facebook and sat at my lunch table, now she laughs at all my jokes, agrees with pretty much everything I say, she also sits right next to me at lunch, I tried acting like a tool as an experiment but she didn't seem to notice she still acted real pally, what does this mean?