The point is not that 12 and 11 year old kids are incapable of being mature. In fact some of them are. It's the fact that the majority of kids this age are immature that makes people think less of them.
Minecraft should not have an age limit. Anybody has the right to play this game. Server owners have the right to allow who they want on their servers.
For example, if I put together a build team, I would not allow anyone under 14 or 15 in it, simply because the majority lack talent and are less mature than older people. That being said, I do not think less of them, and they still should be treated fairly.
