I looked it up and Miyamoto confirmed Adult Links age in Ocarina of Time as 14-15 (15 is the age of social adulthood in Japan, but not legal adulthood), and since seven years passed between Young Link and Adult Link, that would make Young Link 8, (which makes sense, he is a child, I can't really see him being 12 now that I think about it), but now onto The Wind Waker, 15 or 8? He really doesn't look like 15, but definitely not 8 (think of the little kids that are like 5 years old, does that look like a 3 year difference?) so, my guess would be 15, he just looks a lot younger due to the art style, maybe the reason he's still treated like a kid is because he's not quite a legal adult, most adults in America would consider a 15 year old still a kid (not like a 5 year old but still not mature enough to be anywhere close to an adult), as for the school thing, there was also a school in Wind Waker, and if the Elementary thing is true then you could slash Toon Link being 8 out, besides, those kids look no where near his age. And one more thing (I'm starting to ramble), look at the kids in The Wind Waker, look at Link, look at an 5-8 year old kid, and look at a 15 year old, the differences are almost directly proportionate, he just looks young in face, height and voice because of the art style, once again, trying to attract younger gamers to a new generation of Zelda, that's really all there is to it, so my verdict? Toon Link is 15.