I have thusfar avoided giving precise ages. In my experience, it focused people on the wrong thing.
When I say “Jack is a teenager” then when he talks and behaves the way he does, people get it.
If I said “Jack is 15,” then I divide the audience. Some people think “that makes sense,” and some people think “no way does a 15 year old talk like that.” Nothing about the character has changed, but now that there’s a number attached to it, suddenly people reject it.
Same with Sunny. I think of her as “Not yet 20.” Or “very late teens.” If I gave a specific age, people would argue about her.
I thought I knew how old Slim was, but many people hearing his voice concluded he was much younger than I thought (and much younger than the actor voicing him!) The actor is doing his level best to just be a regular guy, not a Heroic character, but for whatever reason, people concluded he was much younger.
But that’s fine with me! If I gave a precise age, then suddenly his performance would sound “off.” NOTHING HAS CHANGED except I gave a number, and now some people don’t like it.
So I don’t give a number. I have vague categories.
Don’t mistake my meaning" I don’t know their precise ages. I’m not concealing something known, I have deliberately avoided pinning down numbers.