If you don't want to, then don't. Always make moves from your deepest instinct. If your gut says its too soon but you feel "pressure" to do so, examine where that pressure is coming from. Is it because you feel that you owe her since you are dating/sexing her? Just because it's christmas? Dating is it's own reward...you don't have to pay to play.
If you feel you want to just from a core of selflessness, and because you just really want to, follow biggies advices. 2 weeks, you really don't even know her..you just like the idea of her so don't go overboard, something small.