You will get memphis before you know it, attrition is so high here and they are going to be hiring a lot of fo's so dont even worry about getting memphis, even if you have to wait 3 months, just suck it up until then. In Class you will place a bid for memphis, if you are awarded it, good, if not when the next vacancy comes out a month later, as long as your first choice is memphis they will change your base to memphis.
I bet you get memphis on your first try.