If your not married before his orders are cut and he's out of A school. You won't be going where he is. They wont' pay for you to move with him and it will be on your dime (fyi E1-E3 really don't make much).
Also be prepared their first duty station could be Japan or Korea and they don't move families there (normally).
If I was in your situation I would elope and then plan a big wedding for later. He's gonna need to fill out a chit for the wedding. They can deny time requested off while in school.
Have your fiance talk to the chaplain. We got married while my husband was in A School in Florida, and got all sorts of reasons from different higher ranking officials as to why we shouldn't get married. My husband spoke with the chaplain, took a financial budget class and took a marriage class before he could submit a chit.
Sweet*Southern*Lady is right. Get married before he gets those orders, even if it means heading to the courthouse for a quick JOP ceremony, with something bigger later on.
Don't give up hope! It CAN happen. Your fiance needs to be persistent. :-)