The Medieval world assumed that there was no childhood, and it treated young people accordingly. Young people behaved as they were expected, and society succeeded. On the other hand our culture assumes that young people are children. We assume that there is a longish period of preparation of children for adulthood. We treat young people accordingly, and they act accordingly.
Today there are truly children.
I believe there is no natural in all of this. People are as society treats them. To the extent that this is so, much hangs on Aries' thesis. At this point in the argument I do not argue against this practice. I simply argue against our pretending that what is a choice is really nature.