My last response was based on your question which nobody here can answer. Your instructors as TBS cannot answer it. You can call MATSG Pensacola and they cannot answer it. A lot can happen between now and when you get down there a year or more from now. And that includes both your own progress through OCC and TBS and possible changes to the Marine Corps force structure, etc, etc.
What kind of wedding are you trying to plan? Is this going to be a $50-100,000 extravaganza or a quiet wedding with a few friends at the base chappel? I personally got married at the base chappel on a weekend that worked for my wife and I and our parents flying in. This required no leave since Saturday was already a day off, and it was a relatively bland event.
As long as the Marine Corps holds the trump card and gets final say on what you are doing any given week or weekend, and by Marine Corps I really mean any officer with more rank than you but perhaps less empathy, common sense, or understanding of your situation, you are not in full control of life events. As long as you understand that, and more importantly, your fiance understands that, you can still manage to plan a nice wedding in advance. You just have to be prepared to lose money on deposits if the date needs to change, or inconvenience family and friends who may have tickets purchased, etc.
I would suggest that the safest bet would be to plan a wedding in P'cola, but even that is a crap shoot, because you could be rolled from one TBS class to another, or depending on the API wait you be kept in Quantico or stashed elsewhere.
Perhaps the best option is the very common secret ceremony in Pensacola by a Chaplain or Justice of the Peace that gets you married, benefits, and living together and then you do a big fancy wedding for the family at a later more convenient date. The family may or may not know about the first wedding.
