Is There an Age Requirement for a Fat Grafting Procedure?

Hello dear!
Thanks for the question and provided information as well.
There is no age limit for plastic surgery, it all depends on your current health condition and your lab tests, but you should be at least 18 years old to be a candidate for plastic surgery. 
In general, you need to be physically healthy and at a stable weight, have realistic expectations, be a non-smoker and your BMI needs to be 33 or less.
l recommend you to make an appointment with a board certified plastic surgeon to talk about your goals and anything you need to know.
Good luck :)

   If you are 18, you could be considered for Brazilian buttlift.  Please find the plastic surgeon with ELITE credentials who performs hundreds of Brazilian buttlifts each year.  Kenneth Hughes, MD Los Angeles, CA

Though there is no age requirement for fat transfer procedures, unless you are over 18 years old, you will need parental consent.

The more important factor in deciding the timing of the surgery is to be at a stable weight when you have surgery.

If you are at your absolute thinnest when you  have surgery, it is possible as you gain weight to your baseline level, then the grafted fat will also enlarge and possibly change the contouring. The opposite is also true, in that if you have the grafting when you are at your largest, you will lose volume as you lose weight.