one of the top surgeons here recommend to experience breast feeding first or motherhood before having a breast reduction.
but when it comes to excercise i dont know of any since i am doing an excercise to make it bigger, hehe.
but have you tried applying those slimming creams applied to your breast so it would dissolve the fats there? BUT it MAY sag it, i think. but those creams got skin thightening effect too, so now i am confused. anyway, just a suggestion, its for you to decide, just pick the right one if you would resolve to this.
so now i feel like i am nothing of help

anyway, just want to share what i heard the surgeon has told because as she say, you may miss alot by having a breast reduction NOT having yet experiencing breast feeding or motherhood.