Character Ages

[HeadInAnotherGalaxy]

That's b/c in Redwall one season is a year 

That hasn't exactly been proven as such.   I think its up to the individual reader to decide whether they interpret age in years, or whether a season is literally a season, and there are four seasons in a year.

Aye, ye could 'ave vone zeazon reprezent four yearz!

[Lutra]

You cannot actually take four seasons and put it into a year, because then, you'd have a 16 seasons mouse who was four years old. That doesn't really work.

Seasons are more like animal years.(IMO of course)

Why does that not work?  A mouse can live four years, but a four year old mouse is quite old!   I think its entirely plausible in Redwall.

[Redwaller]

What we don't really know, is how much time passes between each books.

[Lutra]

That's right, we don't, that's why we can never entirely figure out how long a "season" really is, whether its meant literally or figuratively to mean "year".