I aged mine in the keg for the same time as a bottle all I did was put some c02 in and pulled the valve open about 5 times to let the air out then just aged it for 2 weeks and it has lots of carbonation now.
Good Luck
I just started brewing about a month ago and my first one was an American Wheat Extract kit from Northern Brewer it was so easy to work with for the first time.
Good Luck