You are experiencing something which is quite common during this phase of your development. Once you achieve your adulthood, they might change and normalise or may stay asymmetric. So you should wait till then. And if still asymmetric, might consider cosmetic procedures for correction. Otherwise they don't hamper normal function.
Next Steps
Clinical examination to rule out any lump or swelling in the breast by a breast surgeon or oncosurgeon.
Health Tips
If there are no lumps or swellings in the breast, it is normal developmental process.