In a gaming show, they berkata that Sonic is 15(Sonic was 15 in the comics when he started atau something) and then he had his birthday in the games that makes him 16. But I say 15. And in the comics, he is 18.
Well for the the actual canon he's 15, but since he had a birthday he's 16. People might say he's in his 20's that's because of the franchise's anniversary. That's what I think though...