When will I find out my official AFSC for the Air Force?

I went to MEPS about a month ago and put the AFSC's that I would like onto my list, signed my contract, and swore into DEP. They said that most likely I will leave for BMT in January. Im just wondering when will I find out what my AFSC is going to be. Am I going to have to go back to MEPS to find out? Or will my recruiter tell me?