death and destruction, degradation and entropy, the relentless winds of time.

Is 16 the optimal age? I don't know!

15-18 years old, arm muscles. Around 12-15 years old - leg muscles. This applies to boys. That's what a professor from the physical education department told us, and he seemed like a pretty smart guy. In principle, I described the rate of muscle development based on the experience of one of my acquaintances, so the information is accurate, and that's how it will be.
Klov, as long as there's a barbell and dumbbells, the rest is up to the trainer and time.