異世界転生したら女の子になっちまったけど女の子と一緒だから大丈夫だった (Associated Names)

Subaru Yuuki, a peaceful high school otaku boy, with social anxiety disorder. Reincarnated in another world with ambiguous memories. While thinking, he incarnated as a girl. Looks of a girl. Brains of a boy. It is such a story.