I think you should definitely give this some more thought. I am at the opposite end of the spectrum, and for years I seriously considered getting a breast reduction. I couldn't run without bouncing and hurting, and I hated having to buy XL in shirts, not to mention getting stared at by every man I encountered. I'm less than five feet tall, and used to wear vests and two or three shirts to cover myself up.
I used to think that I could go through the procedure, because I was miserable with back aches and so self conscious about being stared at. Then I realized I probably wouldn't be able to breastfeed if I had the surgery. And I read about other people's stories, and how long and painful the recovery is. Also, the thought of people I knew seeing me afterwards and wondering how I'd gotten smaller also really bothered me. The scarring didn't look too attractive either. I ended up having an emergency abdominal surgery when I was 19, and realized how hard it is to recover from some precedures.
So I rethought my decision, and decided that I didn't want to put myself through that. What if I changed my mind later? What if something went wrong and I got an infection, or had to have more procedures to fix the problem? I also want to have kids, so I didn't want to give up my only chance of breastfeeding. I figured I'd survived puberty and high school looking the way I did, so making it through the rest of my life would be cake after that.
I know your situation is different from mine. But you do have the option of wearing bras that have gel or silicone in them that simulate the look and feel of a bigger cup size. And you also can take them off at night and be comfortable sleeping on your stomach, or working out without all that weight on your back.
It is a shame our society places such an emphasis on breast size, because if it hadn't then you wouldn't be so insecure. As an example, consider how much our society encourages promiscuity. On TV and in movies, people are having sex on their first dates, and when we were growing up we probably worried who would be the first among our group of friends to sleep with someone. But at the same time many males and females are still waiting for marriage. Both types of behavior are accepted by society, except one is more encouraged than the other.
But you need to weigh the benefits against the risks, and decide if you are willing to go through that kind of pain. I know I wouldn't make such a drastic change without consulting my family first. It is embarrassing, especially if your female family members are well endowed, but definitely worth discussing with your family.
The most important thing to remember is that your worth isn't determined by your cup size. We are all concerned about how we compare with our society's ideals, but your family doesn't look at you and see you as a failure just because you're not a C or D. Neither do your friends, and if your boyfriend does then he's probably not worth your time.
As I've grown older, I've realized that I just don't care about my size anymore. I think about it when I go shopping and can't buy the cute little shirts because my bra would show or the XL is too small or I can't get away with not wearing a bra under strapless dresses. but I'm not insecure around my friends or family anymore. I've learned to accept myself the way I am, and I think I'm happier for it.
I don't know how tall you are, or whether you're thin or are a bit on the heavy side, but I've seen all kinds of women with all kinds of body types look good with nothing to speak of in the bra area. I think if you look at different kinds of clothes then you can find something to show off your strengths, like long legs or big eyes. Color can make a big difference, too. Wearing pretty bright colors can bring out the best features in a person so much more so than neutrals or dark colors.
This surgery might be something you regret in the future, so maybe you should wait a few years before making a final decision. I know you stated that you were considering it for the future, and I think that's good. You can have it done at any age, I assume, and I think you will benefit from doing some more self-exploration and discovery. Talk to your close friends about it, and maybe your mother or sister if you have one. Feel free to PM me with any questions. I'm glad I didn't rush into a breast reduction without some serious reflection on the subject.
I also suggest you go see your doctor, someone you trust, and ask his/her opinion. This person will know your medical history, and be able to advise you better than we on this forum. I hope you can make a decision that you will be happy with. Good luck with your dilemma.