While it's possible-
- the odds are that you might have some more breast growth still ahead of you.
Ideally, it would be better to wait until you're done developing. But if they are already very large, and you are getting teased a lot, talk it over with your parents, and have your mom go with you to see a plastic surgeon. The surgery will make your breasts smaller, lighter and perkier - but there will be scars.