I'm still pre-op but this is a topic near and dear to my heart
I am now very well endowed at my high weight and even though I'm 25, the girls are already pretty saggy
God willing if I'm able to jump through all the hoops and get WLS I'm fairly certain PS won't be far behind.
I would say wait for two reasons:
[1] once you reach your goal you may want to do some additional work, tummy tuck or otherwise. A big part of surgery expense is anesthesia - if you wait and do it all at once, it will save you [or your insurance company] some money AND you won't have to go thru the healing process multiple times.
[2] after WLS you will lose A LOT of weight in a shorter amount of time than diet/exercise alone - as i understand it part of this weight loss is due to ketosis which is your body using fat for energy. you may end up losing much more weight from your breasts than you could have ever expected. waiting will ensure that you don't reduce too much for your liking
You've had big boobies for most of your life - as much of a pain in the butt [err back?] as they are you may not be any happier with a A/B/C cup vs. a D/DD simply b/c the fuller appearance is something you're used too.
Hope that makes sense... and is helpful
No matter what you decide, go with your gut instincts and be true to yourself. Good luck!!!!