I joined the RAF at age 23 - at the top end of the age limit. I remember that, before I commenced flying training, OC 100 Sqn told me (at a B of B cocktail party) that the RAF were really interested in the 17 - 18 years olds due to their steeper learning curve.
Funny old thing, most of the younger guys on my Jet Provost course were chopped. I fought my way through to multi's relying on my few extra years maturity to overcome the various pressures and obstacles.
My point is that it really is a balance. Yes, it is a help to be young, flexible and a fast learner. However, flying is for grown ups and that helps too. The skills and experiences (once learned and honed for a few years) don't go away.
I am really irritated by (and sympathetic to) the plight of fireflybob. I once knew a pilot who took voluntary redundancy from BA and spent 17 years running a business. He returned to commercial flying in his fifties and ended up with a B737 command.
It really worries me this trend towards young and cheap pilots and I am sure I'm not the only one. Airlines know the price of everything and the value of nothing these days.
Toodle Pip