What is the ruling on a girl who is 11 or 12 years old shaking hands with non-mahram men?

It is not permissible for girls to shake hands with teachers or to be touched by them if they have reached eleven or twelve years of age, because they are at an age when they typically desire. As for girls greeting teachers without shaking hands, there is a difference of opinion among scholars; some permit it on condition that there is no fear of temptation, while others consider it forbidden.