1. NATURE: according to biology optimal or ideal time window to create a family is between 18-22 years old.
  2. CUSTOMS, CULTURES AND HABITS: some nations and cultures distort or ignore this time window. For exaple create families from 14-16 years old or after 28 years old. These cases have some psychological, physiological or demographical consequences.

So depending on your surrounding culture and your personal understanding and wisdom you choose your way.

But I would introduce.