since its only dec. and there is still time to ask why don't you play a game like the 20 question game. or more than that. ask her questions and ask her what you asked us. but don't just come out and say it. put it in the middle of all the questions you ask and you can make them seem odd or personal to make it not seem so obvious. throw in some other questions about holidays.
some girls are different so why not be sneeky and figure out what she liked
I agree I mean maybe if you are already with somebody you could simply ask your significant other to be your Valentine's. If it's some person that you have feelings for and not really sure how or when to ask i think it's a great idea to ask her/him before Valentine's so it gives you the opportunity to take her/him out before somebody else does.