Hello Addams22 and thank you for your question. You would be a good candidate for a breast augmentation. Please keep in mind that a breast implant is like a ball and it has a certain diameter. Your base width on each side of your chest will determine "how big of a ball" or what diameter implant you can reliably go up to with a socially acceptable cosmetic outcome. The implant will "augment" or increase the size of your breasts to an amount acceptable to you and your surgeon. As for implant placement, I understand that you are very active, but I have many patients who are hardcore fitness enthusiasts and I have them back to their normal routine within a month even after breast augmentation under the muscle. You appear very lean, and long-term, with larger implants, your tissue will thin and you may suffer from implant rippling, malposition, etc as you do not have a lot of soft tissue support over the muscle and then down the line your fitness routine could be disturbed with the need for revision surgery; don't forget the downtime needed to have future surgery and also the costs of the procedure and also time off from work. In my opinion, going under the muscle has many benefits such as decreasing your chances for rippling, decreasing your chances for capsular contracture, increasing your chances for greater longevity, and also a more natural look. Dual Plane is where the muscle is separated from the gland inferiorly and allows the top of the implant to be more under the muscle where inferiorly towards your feet it mainly under the gland and there is no muscle. The benefits of dual plane are basically the same as subpectoral, but allow for better lower pole expansion and slight nipple elevation for cases of truly mild ptosis or slightly saggy breasts. There are many ways to perform plastic surgery and if you are not certain with the recommendations made by the surgeon whom you have seen, I think you should trust your intuition and I would encourage you to seek a second opinion via consultation with a board certified plastic surgeon with expertise in aesthetic breast surgery. I hope this helps answer your question!Sincerely,Dr. Sean Kelishadi