Vic,
I was 25 when I got through (first time by some miracle). I have seen more than a few trainees through the system since then. In my humble opinion maturity and some life experience can only be a help to you. At the end of the day if you fit the stated recruitment criteria, pass the tests and show some promise at the interview then your age is irrelevant. Good luck, although some days the job can give you a beating, on the whole it beats working for a living........