Most of us, with five years of hard training by age 23, have nearly peaked in terms of strength and will make little progress over the next ten years as T-levels are already in decline by the mid-20's, causing strength loss, metabolism slowdowns, and a general inability to gain mass as easily.
Ok, I guess?
I started lifting at the age of 14 ~153lbs (70kgs). Now I am ~200 (90kgs) at the age of 31.
My, by far, best strengh gains have come after the age of 25. (not including the "starting up" gains ) And still,every year I make new pb lifts. ( sets or maxs)
Weight gain has been inconsistent but steady. Bodyfat ratio propably quite the same when I started but has been bigger and smaller during the years.
I've lost almost total of 2years of different injuries and only bodybuilded trough fall and spring, other sports in summer months (jun,jul,aug). Injuries always take you back 1 or 2 steps.
So my estimation was on a dedicated,gifted person not an avg.Joe like me.
If you "Special ed" think that you've peaked at the age of 25, you're just lazy!