why aren't there any tween virtual worlds
Because you need to go do something other than talk to "12 yr old girls" on the internet that are most likely pedophiles.
Probably because you guys are too young to be chattin' it up with strangers.
There are various tween virtual worlds that are available including Dizzywood, Whyville, Club Penguin, Moshi Monsters and Barbie Girls. The choice of entering a tween virtual world will depend on your likes and interests.
Look. i play on wizard101, pirate101 and free realms and i dont care if there tween or not! play what YOU want to play. even if its barbie people cant make fun of you for who you are <3