So, no. The others here are right; Ash's age has been left ambiguous for years upon years. That left people to decide for themselves whether or not Ash was truly aging.
Then BW took that away from us. Its first offense of a string of horrible writing and disregarding continuity that continues to this day. I really, really, really hate it when canon takes my freedom to assume whatever I want about something. It's just horrible.
And yes, of course I think Ash should be aging, but obviously not in real time. I always strictly followed a formula that one full region equals one year. Half-regions like the Orange Islands and the Battle Frontier I considered a matter of a few months or so, no more than six. That would make him around 15 in BW, and it would've been a good fit considering the notably older game characters we got for the games. But why do a silly thing like coincide with your source material when you can just give a middle finger to continuity and be lazy by repeating all the mistakes of Kanto that you learned not to do in the past, right?
But I was happy enough with his age just not being stated at all. That was the happy medium; the way we could all assume one way or another and it wouldn't become bothersome. Now we're expected to believe Ash traveled four and a half regions and a Battle Frontier all within a year's time despite the past evidence suggesting otherwise.
And honestly, it's stupid. I understand wanting to keep Ash young to be relatable to kids, but there's plenty of main characters in shounen anime and manga that age to varying degrees, and they become no less relatable or fun despite that. So I think it wouldn't be the end of the world to put a few years on Ash. He can still be his same ol' self even as a teenager because he'll always be an idiot, and we can all rest easy knowing there's an actual, sensible passage of time going on in the show.
Because this is a journey show. Time tends to be a big element in ongoing journey shows. There's progression shown in everything... except the matter of aging. Why? Because the writers are dicks.
Basically what I'm saying is that BW ruined everything and I hate it for doing that.