Yeah it's true, if you smoke pot heavily at a young age it stunts your puberty and growth I think, the weed affects your developmental part of the brain.

I have friends who started smoking at a young age and they still look like they're 13, even though they're like 20, 21 years old. It's funny, they try to grow facial hair to compensate and it looks like chin pubes, because the weed slows down the facial hair scene as well.

I started smoking constantly at age 18, and I haven't changed a bit since then.

So yeah if you start smoking at a young age, you're gonna look young when you're older.