It's something of a cliche (and one that is not appreciated by many fans of the genre) that girls' school stories tend to be rather homoerotic. - Angela Brazil did not help things by calling a major character Lesbia. But I really enjoy that element of women looking at women that you see throughout the genre - I've long held that Antonia Forest is the writer who first taught me to look at women.
I was unprepared for this scene from L.T Meade's A Modern Tomboy, though. I can't find an exact date, but it's somewhere before 1914.