How big should a 16 year old's penis be Watch
National average is 5 inches for an adult male (21 years +). Boys don't stop growing till 21. Orgasm for a female is achieved by the rhythmic thrusting of your pubic bone against her clitoris, not by how long your penis is.
Having said that, TSR is not really the place to make such inquiries. Here is a link to the relevant NHS website; I suggest you have a read of it.
Of particular interest to you will be the following:
“There are no average length figures for teenagers because people grow at different rates.
Research has found the average erect penis size varies from around 13cm to 18cm (5in to 7in).”
There is no health, moral or legal imperative dictating how large your penis should be at 16, providing it does all the things it's supposed to do.
5-6 your decent
7-8 defo bigO