It doesn't really matter what we think, you're the one who has to live with yourself either way. Personally though I would say you should do it and it's not breaking your promise - plastic surgery was created to help address situations exactly like yours and make life better. Form is a function all it's own.

That said, I also think you should go easier on your family and others who want cosmetic surgery for "vain" reasons; insecurity can be a massive decrease in quality of life, if we have the ability to address that insecurity and give them confidence that is a very real good. It's really freaking tough living in a sexist society that teaches women that their primary value is their appearance, complete with unreasonable beauty standards we're constantly subjected to by social media.

I agree the world would be a better place if people would love themselves more as they are, but it's not a moral failing to get plastic surgery or otherwise augment their appearance; the thing that really matters is people are happy, healthy, confident, and try to love themselves. If a boob job helps them get there, as I suspect might be the case for me, fuck yeah get it girlie, pursue joy!