Young (18) but Uneven Breasts

In my opinion, you would need a lift and reduction on the right to roughly make them equal. Subsequent to this youcould udnergo bilateral augmentation with implants (saline due to your age) or consider fat grafting for a  subtle but autogenous tissue augmentaiton without implants. This may take more than one session.

Breast asymmetry is a very common problem for a lot of women. In your case this is compounded with asymmetry with involves both size and shape. I would also point out that you also have a tuberous or constricted breast deformity which needs to be corrected. There are numerous different ways your case could be done. I would recommend a combination periaeolar augmentation and mastopexy which will address both the size and shape issues. Make sure to visit with several doctors and spend time looking at their before and after pictures with examples of cases like yours.

A breast implant on the smaller side won't have the same shape as the larger side, which sags.  A combination of augmentation for the smaller breast and a reduction with peri-areolar lift on the larger side can improve the symmetry.  The reduction is useful because it lets you have a more similar sized implant on the two sides so they age and settle more similarly.  It is best to do this when you are at an ideal weight.  Changes in weight will change the result of the breasts.