Huh, I feel like it'd make slightly more sense if Kyouko thought that Yuu was a girl back then, but unless the translation is off, then she refers to the child version as "Him" once and also calls him Yuu-Kun.
Also, seeing some haters here, let the story breathe for a bit before you whine about one of the leads, or just... go away if you don't like the premise of the story? Rather than sticking around long enough to smugly opine about keywords.