Rephrase 1
People keep growing until they’re about 22 years old.
As people get older, their spine and muscles can get weaker, which might make some people look a bit shorter.
Rephrase 2
Growth doesn’t stop at puberty; it can continue until around age 22.
When grown-ups get older, their backbones and muscles can become bent or weaker, so they may appear shorter.
Rephrase 3
Most people keep growing can until they are 22 years old.
With aging, the spine and muscles may lose some strength, which can lead to a shorter height over time.