Damn, so following from my last comment in the last chapter, there's a rotation schedule in the guest bath, and it wasn't even the girls' turn, even more of her fault, but at least with her dad barging in (who pretty much stated the guest bath is the best one for him to use over the family's one in the castle, somehow), she realized her own fault then and there. Of course, with how harsh the father was, that she'd listen to his reason over MC's, but I'm curious to know what her skill is that's holding her back from becoming a knight.
I don't think he meant any ill will, just that he's looking out for her future like any parent who cares for their kid, and apparently it's bad enough that she can't even leave her own home.