I've said almost the exact same thing to her. SHE HATES IT. Feels like I'm never worried about money, that I'm a spendthrift.
I don't think this is the time. It looks like a desparate move and like you are trying to buy your way into her heart. Besides, it's not really the boob job, it's about her needing higher self-esteem.
When a woman hints at needing this or that done to her body, she's saying that she doesn't feel as confident as she wants. She hinting for you to reassure her that she's the hottest thing God ever created.
As she gets older, she will need to be told that she is beautiful in several different ways. Be specific. Try something other than what I call the "Husband's Common Compliment"(which is a fall back b/c he's not really using his brain). She gets dolled up and he says, "Oh yeah, you look nice". (I started to add Edith's name b/c I can almost hear Archie saying that, as if his arm was twisted)....
I'm not saying you do or don't in regards to all of this. Just throwing my two cents around.
It is not about what you feel should work in your M. It is about doing the work that gets the right results. Do what works!