Facebook Birthday wall post or not (it's a girl I like)

I've had my eye on this girl all last semester, but have only talked to her once. When we did talk, it was a very pleasant conversation, and we exchanged a lot about ourselves. We're Facebook friends now, but that's it. Haven't talked since. We don't text or anything.

All that to say, her birthday is tomorrow, should I post on her wall? Or is it cooler/more mysterious to not post?