Is it easy, hard, or impossible to determine the actual age of a person from a biological examination? I'm not talking about the obvious wide divisions (infant, little child, older child, teenager, etc.) but within a year or two.
For example, if you're presented with a boy claiming to be 17, would it be possible to determine for sure that he is in fact 15? If yes, is this limited only to "growing years", and precision would drop drastically once you pass to adulthood? (for example, presented with a woman claiming to be 24 and she is actually 22)
If either or both are possible, what would the indicators be?