You are not answering the question
The question was, and it has been asked on here, is there any evidence of 11 year old girls beating to death a large male twice their size
You have not provided any evidence of that
Do not change the goal posts
12-year-old boy violently assaults Southbridge man with baseball bat
There's a good one.
Oh, I can hear your lame rejoinder already: "But that was a BOY! This was a GIRL!"
Pre-refutation: At the age of 12, hormones have not yet fully kicked in, so the difference between a boy and a girl is slight.
And your next lame rejoinder: "But he had a BAT, she had NOTHING."
Pre-refutation: Not true that she had nothing. She had at least 10 other assailants. That could very well prove to be more effective than a bat. Further, dude did not know if she had a knife, which would have been FAR MORE effective than a bat.