Oh it will be so lovely to have a baby and share your Christmas traditions...oh that's right, you have no idea what they are, so you? 
YAB extremely U.
A baby is a human being, not a doll or a fashion accessory, not even just a much wanted element in your life - no matter what your age. I think you know this, else you wouldn't be posting on MN.
Slow down. Get to know each other properly. Find out what he's like in January ffs before you even think about binding yourself to this man in the most decisive, lasting, profound way possible.