I'm 13, but I dont see myself as immature...
To be honest, I dont think people should judge immature people and say 'Ohh they're obviously a 13 year old' or whatever, as there are 20, 30, 40 year olds that act immature.
Immaturity, yes, is more comman in kids but you have to remember that there are adults that are immature too.
And as said earlier in the thread, yeah, the community has grown, making it SEEM like theirs more immature people... but its just gone up in scale WITH the community.