get bigger?

i know this is probably in the wrong section but im 20 and i have a condition that slows testosterone production the doctor said my body is probably at the age of 15 i have a 7.5 by 5.5 inch dick just wanted to know how much a regular 15 yr. old would grow by the way i have little armpit and pubic hair

in theory you can get 10+ or just stay the way you are
I hope you aren't 15 years old anyway