Alexander the Great inherited his kingdom at the age of 20 and went on to conquer the rest of the civilized world at the time. In fact, he cried when he was told there was no one left to conquer. He must have possessed some amazing leadership skills to have his men fighting for him for 10+ years.
Louis XVI and Marie Antoinette were 20 when they inherited their throne. They were given a raw deal to be sure, ill prepared and a kingdom already set up for failure. I’m not sure it could have turned out much differently. But still, to trust 20 year olds to run a kingdom!
I think we are failing our youth.