the Age of Maturity according to Gurdjieff

From this time on, that is, from the moment the process of his development is finished, a man becomes personally responsible for all his voluntary and involuntary manifestations. According to laws of nature elucidated and verified through many centuries of observation by people of pure reason, this process of development is finished in males between the ages of twenty and twenty-three, and in females between the ages of fifteen and nineteen, depending on the geographical conditions of the place of their arising and formation.

Meetings with Remarkable Men / Chapter "My first Tutor"