Started in 1853, Samson Raphael Hirsch School was a Jewish Orthodox school in Frankfurt am Main . It was a secondary school for boys and a lyceum for girls of the Israelite Religious Society .
Mizrachi Yavne started in 1902 in Vilno, girls school was in Slobodka, Kovno; not sure of the founding year.
BY schools had 50,000 students in 1934 Poland. Seems like BY achieved mass attendance comparing with other smaller schools. that probably means poorer girls. But the idea of girl education was clearly there before. And note that better off people might have used private tutors.