Although there is no Age set in stone for a hair transplant procedure, I do tend to see a lot of patients in their mid to late 20's. It's important to medically manage your hair loss if you are interested in a hair transplant procedure. I have performed an FUE procedure on a patient that was 79 years old. So you have a lot of time before you are "too old" for an FUE procedure. Whats important is the quality of your donor zone and that is different with all patients.
If you are completely bald at the age of 19, and there isn't much more hair to lose, hair transplant surgery may be an option! There is no special age where you can or cannot have surgery. It all depends on your examination and understanding of the risks involved.
FUE is just a method of harvesting the hair. There is no age limit.
What age is ideal for FUE transplants?
I have transplanted men as young as 21 (rarely) and as old as 88 and FUE of strip surgery works well and the grafts grow. Man of all ages want to see the man in the mirror with hair and don't doubt that. The man in the web like below was over 50 and there is no doubt that the man in his mirror he like more than the one months before. This was done in just one session.