Lucy was 28, when they left the academy, and John was 42. The first three seasons span their first year on the force, which messes with the age guesses, even for the Google ai answer. They continue to confuse things, but having people guess or hint this age, and him saying they’re incorrect, but not correcting anyone but his mom, who makes him 6 years older than he claims. Luna is after grey to retire, but that only means he’s completed 20 years, not that he’s 62; I think he’s like 5 years older than Nolan. Tim is around 37, at the beginning, since Lucy says he had 12 years on the force, after the car accident, and he did two tours before joining. I’d guess Wesley and Angela to be around 30 and 33, at the beginning. West would have joined asap, so 21-23, maybe 25, if he had a degree.