Can my penis grow 6 inches after 21?
According to what one man and his Quora answers say
I can give you some facts about penis growth without knowing your age.
The size of an unerect (soft) penis bears very little relation to its erect size.
If it looks small, try actually measuring it. To do so, get a ruler or tape measure and, when erect, push the tip into the top of the penis where it meets the body, and then read the length at the end of the head (glans). This is the only way to measure the penis, not from the side, not from underneath, and not, as some guys seem to think, from the perineum (or taint).
Most penises are around 5 inches long. but it's not 6 inches penis size. Many fall outside of this measurement, both larger and smaller, but it doesn’t mean they are any better or worse.
You could try trimming your pubic hair a bit if you have a big bush. That way, more of the penis can be seen.
If you are overweight, losing a few pounds can help the penis appear longer as it is no longer buried in excess fat.
If you’re still young, there is evidence that suggests that the penis may continue to grow until you are in your early 20s.