Board Thread:General Discussion/@comment-30033404-20170608021753/@comment-29296394-20180531212840

I believe that Hanako is in the same year as Ayano, because she refers to him as 'Senpai' so it means Senpai is older than her. And we know Hanako is younger than senpai because it says that she is his younger sister. Hanako was originally enrolled in a different highschool, but she may have been in the same year as Ayano at that school, and the same year in Akademi High.