Serious difference in size of each of breast

Thanks for your question. As you begin/continue to develop it is likely that things will continue to evolve and become more alike. Once you are 18, it reasonable to assess and see if there is enough of an asymmetry to consider surgical correction. No one will want to do anything prior because there is still a chance things can change. If surgery was done prematurely and things changes for the worse, this might be hard to correct. This size is not enough however to cause symptoms usually. Insurance will not cover a reduction unless there is quite a lot to remove.

In cases of size difference between the breasts, it's best to wait until the breast growth is complete before one considers surgery to fix the problem. In most patients, breast growth is complete by 18 years of age, but in some cases, it will not be. If you go 1-2 years without a change in your breast size, then your growth is probably complete. If it's noticeable, then it's probably worth learning more about your surgical options. If the asymmetry is small, it's often not considered a big enough problem to warrant surgery (no two breasts are exactly alike anyway).

You are correct that sometimes large differences in breast size is considered a condition called Breast Asymmetry. Sometimes these differences can result in back pain, neck pain, difficulty with clothing choices and daily activities such as exercise. Although you are young, it would be reasonable to see a Board Certified Plastic Surgeon with your parents to be evaluated for a possible future procedure to correct the asymmetry. In order to make the breasts more even, sometimes the smaller breast is enlarged with an implant or the larger breast is reduced with surgery. Sometimes both of these procedures are required and even sometimes a lifting procedure is performed if one side droops more than the other. The timing of the surgery will depend on your growth status and whether you and your parents feel you are ready. The good news is most of the time the symmetry is improved enough that you can look even in clothing and bathing suits. Patients who have these procedures are typically very satisfied

You have a condition which is not uncommon and very treatable. At your age the breasts have not yet finished their development. Consequently, if possible I would try to delay having anything done until the development is complete. That will prevent having something done and then possibly needing a revision later after complete breast development.

That having been noted, I have treated a number of young women in your situation. For these women waiting was not really an option. The amount of asymmetry was enough to be noticeable in their clothing and especially in their swimwear. Because of this they were not able to participate in normal recreational activities at the lake, beach etc without being excessively self conscious and surgery was justified to allow them to continue a normal lifestyle.

There a number of treatment/surgical options. Discuss your concerns in detail with your parents and if they agree, seek out a board certified plastic surgeon for a consult. You're already on the right track by looking the ASAPS website. All the plastic surgeons who are ASAPS members are board certified in plastic surgery and have demonstrated a particular interest in cosmetic surgery. Although your situation is not strictly cosmetic, the experience and skills needed for cosmetic breast surgery are invaluable in being able to get you a pretty result.

Best wishes!