When epiphyses close
The long bones
involved in height
have a shaft (diaphysis), flare end (metaphysis), and epiphysis (end cap of bone).
When the epiphysis closes, the bone length will no longer respond to heightening growth. But it is not a precise science. Two main bones that affect height are femur and tibia. Each one can close anywhere from age 15 to 22. Soc needs to see x-rays, growth curves and take full hx.