Umm... Don't listen to idiots. That's what people who claim a game's age rating affects it quality are. Yeah. Gran Turismo 5 is a PEGI 3. Great game. Sonic Generations. 7. Great game. Smash Bros. 12. Great game.
If anything I think that having a higher age rating is more likely a sign of lack of quality (think of the 18 rated grim dark brown awfulness of COD, although that in no way suggests that all higher rated games are automatically worse, there have been many brilliant games with higher ratings) than of high quality. Those who claim games have to be "gritty" and "mature" to be hardcore aren't "core" gamers. They're whiny newbies who want to conform to some bizarre notion of "cool" and think that anything that contains colour or imagination is somehow "uncool" and therefore "worse"
If I want to escape from colour and joy then I'll go and stand around some 1960s tower blocks, not play a video game. Real gamers care not about image, they care about fun.
Real gamers like Kirby.