Just give her a quick Happy Birthday and Happy Holidays. Doesn't have to mean anything. It'll give you bragging rights that you're a nice guy...
"So tonight, when you're wondering what to say, or how you look, or whether or not she likes you, just remember, she is already out with you. That means she said yes when she could have said no. That means she made a plan when she could have just blown you off. So that means it is no longer your job to try to make her like you. It is your job not to mess it up."
-Hitch