I was in elementary school from 1962-1968, so no pants for girls. We wore dresses or skirts with blouses. It gets cold in New England so I had a large collection of tights, and we were allowed to wear pants under our skirts for going to and from school- but pants went in your locker for the school day. I can't remember if we were allowed to wear pants in 7th grade, but I know by 8th grade we were allowed to, provided it was part of an "outfit" and not jeans. By the time I was in high school (10th grade, 1971) we were wearing whatever we wanted, and good luck to the administration that tried to stop us!