Self conscience about my breasts, should I seriously consider surgery?

Alright, I'm a 17 year old with 34DD breasts. Gravity, being the cruel wench it is has taken its natural tole already. They don't look terrible, but they do affect my self esteem. I've been reassured time and time again by my significant other that he finds them attractive and still I worry about what they'll look like in a few years. I don't want to be 21 with sorry-looking breasts. Plastic surgery has crossed my mind (a while down the road of course) although I personally feel like it's a selfish waste of money, or an embarrassment, I don't want to be counted as another woman who's had a breast augmentation just to enhance her appearance. Plus, surgery frightens me a bit for I have never really 'gone under' for anything before. I'd very much appreciate any thoughts, experiences or opinions on the matter.