Most scary flight I had was with a very young pilot officer captain on an RNZAF Dakota. The A4 pilots out bound chose to drive back by road.
Certainly in the mid 1980s, it was not uncommon for 20 year old captains on the F-27 and the Andovers. At NATTS , at the ripe old age of 25, I was the oldest on the crew (excluding the Trapper/screen) on a Friendship overseas route trainer to Australia.