Be careful of generalising.
An aquaintance of mine is 22 years old, a QFI, examiner, winner of numerous flying competitions, and has about 3000 hours. He's doing a degree in aerospace engineering as well and likely to graduate in a year or so. Oh yes, and he has test flying qualifications - I examined him and had no doubt at-all about his competence, nor have since. Presumably the panel who authorised him as a PPL examiner didn't either.
He's not as it happens a school CFI - the CFI at that (UK) school is about 20 years older with 3 times his hours and far more experience, but I can't see any reason he couldn't be. I did see him tick-off somebody who was old to be his grandfather for cutting somebody up in the circuit - it was a polite and fair ticking off, but you should have seen the offenders face
My point really is not to equate age with experience (or competence), they often go together, but not always. Having been running flight trials since I was 23 - at which point I was a graduate with 3 years professional engineering experience and a dozen types in my logbook varying from a glider to an EH101 (okay, the latter as observer on somebody else's flight trial at Westlands, but it still counts! - FTEs learn on the job), it's a subject I've always been fairly sensitive about - there are some arrogant people out there who naturally assume that youth equals inexperience or inability. Sorry, they are wrong. Not even slightly wrong, totally wrong.
Experienced, well trained, well managed aviation professionals please. Who on earth cares about their age?
G
N.B. At 19, as I made a complete balls up of a Bulldog sortie, my QFI rather forcefully reminded me that at my age some people were already Aces in the Battle of Britain. That would have made them about 23 at the end of the war.
N.B.B R J Mitchell was Chief Designer at Supermarine at 25 I believe.
N.B.B.B. Yes, it is a sore spot, and I don't care admitting to it.