I'm 40 and I've been dedicated lifting for 15 years. I was always really skinny with decent muscle quality but it was hard for me to get bigger until I got well into adulthood. I'm not "big" but I've done a lot with my narrow frame.
I've been out of the gym with a hernia since October. I had surgery last week and will get back in the gym next month. Can't wait. Besides intentional rest, shut downs, and vacation, I've been lifting at least 4x a week for these 15 years, and I stopped skipping leg day years ago. These few months have been really hard on me.
I graduated HS 6' 2" 155 lbs. When I started lifting I was a sloppy 180 lbs. Desk job helped things to get away from me. At my peak, I was a really lean 195 lbs, but that's too much work and diet discipline. Now I maintain a pretty lean 185 lbs with as little effort as possible. My workout sessions are 40 minutes, usually, a push, pull, legs, rest split. I found lots of diet hacks (please, ask me about them if you are looking for some). Etc.