Fat Graft Breast Augmentation is NOT recommended!
Fat grafting has been performed for many years and in many different areas of the body. Its popularity really "took off" in the mid 1980's when liposuction began, providing lots of "available" fat that otherwise was discarded. Of course, the most ethical and scientific-minded plastic surgeons realized that the high-vacuum "standard" liposuction aspirate consisted of mostly dead fat cells that had been "boiled" at room temperature because of the extremely high vacuum. Freezing the fat "for later use" further damaged any possibly-intact cells because of ice crystal destruction of the fragile adipocyte cell membrane. So the expensive "grafted" fat was really a slurry of your own dead cells, intracellular lipid (akin to Mazola oil), and fluids. Little or none of this actually survived, but it took a patient's body months to years to fully remove the dead debris.
By then, the "surgeon" was on vacation with your absconded funds! Pretty sad, actually.
Fat grafting can indeed work, but only if harvested carefully under controlled (low-vacuum) atraumatic conditions, and implanted in droplet-by-droplet amounts that allow proper oxygen and nutrition to the transplanted fat cells so they survive. Simply shooting in blobs of mostly-dead fat won't work. And even when done properly, it takes lots of tiny grafts and lots of time (and money) to actually build up volume that can be seen or felt. Some of the fat dies, even under the best and most stringent grafting conditions. Meaning: multiple sessions are virtually always necessary.
Storing fat for use later requires these same stringent harvest conditions, as well as cryopreservatives and liquid nitrogen storage capabilities that are frankly outside the scope of most non-research-oriented plastic surgical practices. Simply putting your liposuction aspirate into the surgical freezer does not work at all! When this fat is used, your body simply ends up removing the dead tissue cell by cell, molecule by molecule, until only scar (and little to no volume increase) and perhaps calcifications remain.
In the breasts, scar tissue and microcalcifications that form when fat grafts die can interfere with the detection of breast cancer via mammogram or other technique. This is the precise reason that fat grafting for breast augmentation is bad at worst, and controversial and potentially bad at best.
There is a reason that the vast majority of ABPS-certified plastic surgeons utilize saline or silicone breast implants for breast augmentation. (And it's not because we're outdated, out-of-touch, or not embracing the "latest and greatest and up-to-datest" developments)! It's because we truly care for the entire well-being of our patients and do not wish to cause them harm that may come to haunt them in years to come. For a woman at age18, I certainly hope you have many years to come! Fat grafting is something every ABPS-certified plastic surgeon is not only aware of, but likely performing in our own practices. But not for breast augmentation.
BTW, "stem cell" augmentation is a new "twist" on BA via fat grafting. It's even more "latest and greatest!" Except in a few rare research instances, "stem cell grafting" is mostly hype by a few practitioners trying to steer more patients like yourself towards their practices.
But, don't take my word for all of this--see several ABPS-certified plastic surgeons and see what they say. Perhaps you will begin to see a consensus emerging!