uhhh just report them to the school? just make some legal threats and they will stuff themselves and suspend all the kids. or yell at them. just tell them that if they fail to address this harassment/threat issue they could be held liable for the results.
you're afraid of a child with a knife. why not choke slam the toddler into oblivion if you have superior tactical fight knowledge? *tips ULTRAdora*
i live in a place with freedom, but i've always thought that "year 11" "junior year" so they'd be like 17.