I would say don't start lifting heavy until 17 or 18.
While I usually don't train to failure, a month or so ago I just wanted to see how many chinups I could do, so I did one all out set and I got 15. That's palms facing me, hands less than shoulder width apart. I should also add that these were full reps, so my arms were completely straight in between each rep. Lots of people don't go down all the way.
IronFist
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<BombScare> i beat the internet
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