I think what the dad means is like he doesn't want her to regret or make 'impluse' decision? like giving her chance to think throughly, if she actually want to become a girl and indeed she doesnt regret it, or just I'm a girl then after the change she will regret it.
Like I mean from what I read he want to say if you survive the ordeal from other people the way you are now you can proceed to next step, if you cant take a pride and said I'm a girl meanwhile looking like a boy, how can she survive in future when she changed wholely as a girl?
I think the father knew Akira is very passive, he want her to overcome herself, and stand on her own?
If you stay like this in future you will be crushed, along like that.
He doesn't want Akira regret it after it become irrevisible.
I know hair can be cut, but operation? no.
So...think as hair a permanent thing first along like that.
He doesn't want Akira doing it halfway, it's better to set the foundation now smtg like that??
I mean he asked her properly, she can't answer, that's why he doesn't agree.
I think he will agree when Akira found the answer.
Idk did I misinterpreted it?
Maybe I'm wrong.
But the bad thing is, Akira felt bad, since she doesn't look like a girl which she wants now, she feel weird.