She is, however she has other siblings. Presumably due to her (Daichi's) efforts she was put in front of the succession for now at least. Its kinda hard to tell because simultaneously she appears to have living parents and also they have NEVER been shown despite several world ending events having happened within 30 feet of their capital. We've only ever met her and her sister so far in the translated story I've seen. We never hear they have died, and she never ceases to be a Princess. So she appears to have a Peach kinda thing going on.
@HDMI1
She probably has been a princess from birth, but not the first. So then she just went by her next highest prestigious title since she wasn't directly in line to the throne.
@Wolvenworks I think that was probably after the dragon incident. Obviously she didn't do everything to solve that since we have this kind of MC wandering around stealing most of the glory from honest, hard working characters like "Haha, cheat powers go brrrrr." But she contributed a lot in the leadership of the city while it was happening, so I think her dad stepped down and let her take the throne or something? Been a while. Someone feel free to correct me if I misremembered any of this or missed something.