And read it now. Yep, it hurts, but I really can not say I am surprised. This is very Mei-like. I also do not think this is bad writing, since it has pretty clear internal consistency.
Fipse
"Inheriting the academy became something I wanted to do of my own will." That being said, as Klice stated, we already discussed at length what Mei's social position entails, but of all that we covered I would want to bring one possible explanation as to why the marriage.
Female heiresses inheriting the business in lack of male heirs is nothing unheard of in Japan, however, Mei is not just a woman, she is also very young. How many CEOs do you know who are just fresh out of high school? Her fiance is older, from a prestigious family himself, a second son (so he will not be bogged down by running that business), and has management experience. The grandfather specifically selected him because he has an unimposing, gentle character, and he would serve as practical help for Mei, while the union alone would put business partners, boards and parents of students at ease, since they would know a high schooler is not running the academy unchecked.
I know I might sound boring bringing this up again, but you really can not have a lesbian who is dating her step-sister openly as the charwoman of a prestigious girls' academy. For one, gay and Japan. Two, step-sibling relationships are viewed as actual incest by many people, and are generally not socially acceptable (even outside Japan, even if heterosexual). I mean, name me one prestigious school anywhere in the world, east or west, that is run by an openly gay person. Let alone a gay person who is in a relationship with their own same-sex step-sibling. It is stupid, and it is not something I am fond of, but such is the world at present.
Mei basically has three choices, choose family and duty over Yuzu (as she seemingly did here), choose Yuzu openly (in which case her dream of running the academy is finished), or try to compromise (somehow convince the boards, any potential investors, and the parents of students that someone as young as her is up to the task, break off the engagement and come clean to grandfather she does not wish to marry; then she would be able to be with Yuzu, provided they keep the relationship a secret from the general public).
Your comment reminded me, the only reason she has to do this is because of her father, she has to do all this shit because her dad decided to do his thing and let a teenage girl have to shoulder everything. Regardless of if he loves her that is a giant dick move.
Even if it meant he had to do something he hated a parent's job is to protect and provide for their kid, this is the opposite of that.