FWIW
60 plus or minus.
Transitioned from mil flying with a fair bit of P1 time in my mid thirties...
Civvie Command in my late 40's on a Long Haul wide body (so after 15 years of civvie flying but with over 25 years of flying in total)
Last Type change 7 years ago, last recurrent check last month.
I think redsnail sums up checks, etc with....
"Am I finding it difficult to pass checks?
No. I know the standard that is expected so experience plus motivation to do well ensures a good performance."
And the experience is the big thing...If you start flying in your teens you are still carrying a hell of a lot of experience around even into your 50s plus.
As for thrusting young cadets..there's an old story about two bulls in a field..