Why did he and she became a person?

So the protagonist who was mistakened for a boy who is actually a girl Mari Haji was always mistakened for a boy in her grade school life which was very crazy because she changed her ways from being a boy to a girl but not through trans-G because she didn't liked it. So as she gets into her high school life she becomes a type of girl who was loved by a girl during her grade school life and now one of her childhood friend which in the end he realizes he loves her not just a friend but instead a girl. She then reached the part where she has to choose one of them and then she chose the right path to her destiny using her faith in her heart and mind.