Shion aside ... Yayoi may have to think a lot of possibilities (up to a possible confirmation in future episodes):
- That she was a lesbian for a long time
- It is just that Bi
- or simply that it was straight BUT became bi to love more girls after an event that will shock ... men
by'll know more in the next episode so it is clear that if the flashback have seen in intimate relationship with a of girls her group ... I think ALL THE WORLDS will have no doubt made her a lesbian