I´m sorry, my bad.
I ment to say that it starts around 13, and ends around 16 or 18.
I got those averages from my own experience when I was young (i´m 27 now).
It could start around 9 or 10, but that was early for most. Normally shouldn´t it be around 12/13?
Maybe it changed in the last few (plenty
) years.