What is magic about delaying surgery until I am 25?

If you are 19, neither the surgeon nor you know what is going to be your final hair loss pattern so decisions made at 19, mean (1) possibly using up your donor bank of hair, (2) having a hair transplant every year as your balding pattern progresses which is does in many young men.  When a man reaches the age of 25, their hair loss pattern is often evident and knowing this allows the surgeon to make a Master Plan not only for the hair loss you have now, but for the future prediction of your hair loss from the diagnosis of your future loss pattern. Donor grafts must be saved for the future loss predicted by the surgeon at 25 years of age?