@
shinya78: Well, even "Baka-Updates" is also using "Shoujo" for "女子" for some reason.
Maybe its the case of specified-kanji reading by the Author (aka., the Kanji is supposed to mean "Joshi", but as per Author it should be read as "Shoujo"). If i am right, these things do happen isn't it, where while the Kanji is read differently, the Author specifically provides an alternate reading for it.
Well, considering that while the FMC is an older girl along with all the other girls (aka., a "Joshi"), the Girl's School seems to be for young girls (aka., "Shoujo").