Re: Is Ash ageing? -
Yup, he isn't ageing.
If we do see him age it'll be one of those age jumps that I've seen a few times in anime. The guy is this age for a lot seasons and then one season the guy grew up and what happened in between doesn't matter or is vague. Kind of like Dragon Ball when Goku is a kid and then he just grew up. We didn't see much of his teenage years. Just childhood, and then he gets married plus the fights.
Another good example is Rugrats and All Grown Up.