Can my uneven breasts be fixed? 19 years old. (Photos)

Thank you for the question and for posting pictures. You do demonstrate quite a bit of asymmetry with regards to breast size and nipple location. This can be improved quite a bit. However, a few things should be kept in mind for patients with large size discrepancies. 
First is to seek an in person consultation with a board certified or board eligible plastic surgeon. Next, is to make sure the breast has stopped growing in size. If there is no significant size change in over a year then the breast is likely done growing. Most surgeons would not recommend a procedure until the breasts have stopped growing. Finally, an appropriate history and physical examination should be done to ensure there isn't some sort of disease process occurring. This is unlikely unless there is a rapid growth in the size of one breast and/or there is an abnormal physical examination (i.e. breast masses, skin changes). 
Assuming all these are negative, a patient would then need to have a discussion with her surgeon regarding her goals of treatment. In your case, you would need to decide if your primary goal is symmetry or symmetry and volume. If your primary goal is symmetry then you may be able to get reasonable symmetry with a right sided breast reduction alone. If your goal is symmetry and also larger volume than you currently have on the left, then you may need to consider a left sided breast implant and a right sided lift/reduction. You should also keep in mind that this may require multiple surgeries to accomplish. Again, an in person consultation with a plastic surgeon will allow you to receive appropriate medical advice. 

Thank you for your pictures. In my opinion, it may be wise to have a right breast reduction to match the left breast .  Best wishes