What happens if you kiss a girl and she doesn't acknowledge it?

I've been seeing a girl for 2 months now and it's starting to go in the right direction. We seem to be dating but not using the word date. She flirts with me from time to time so I know she likes me.

Anyway I recently kissed her by surprise and she brushed it off as a joke. I don't know what this means. Does she not like me? Was she just shy? Doesn't it help knowing that she is asian and so cultural differences may complicate how one advances?

I really need some advice because I really like this woman.