Hi - There's no clear answer here, except that waiting to have BA leaves you more options and less risk, no matter how you view that risk.
A gg takes several years for her breast development to complete. I haven't had BA and over 10 years later I'm a large B/small C, and I'm happy. However, I must have asked myself the question almost daily whether to have BA or not. Same with FFS, but I'm in the middle of that inquiry again/again/again . . . Sooo, like a lot of my natural sisters I'm hooked by Madison Ave's clamor for me to be the more perfect woman that they know I want/need to be. I hear them now, "Come Rachel, come - enjoy, spend, and oh, did I say spend?!
It's not all about the money, but the the beauty industry (the so called keepers of the "beauty" flame) are in business for the same reason Goldman Sacks, Exxon, Piggly Wiggly, etc. are - to make a buck! Your decisions and all us girls' decisions about the body beautiful are as much about filling someone's piggy bank as it is about legitimate concerns about appearance, decorum and taste UNLESS we are careful not to let the sirens of beauty beguile us to be in their perfect images.
This does not diminish your concerns/needs/dreams; the trick is to be sure you satisfy yours, not theirs. All that said, there's nothing wrong with a
little hedonistic extravagance either. Sometimes jewelry and shoes just follow me home for no reason I can remember.

AND OF COURSE, if BA will make you feel better about yourself, then go for it!
Take good care my dear and remember that you are already beautiful,
Welcome to womanhood . . .
Rachel