Boku no Kanojo ga Majime Sugiru Shoujo Bitch na Ken

With nothing left to lose, ordinary high school student Haruka Shinozaki confesses to beautiful, diligent class representative Akiho Kousaka and to his surprise she accepts. Kousaka takes dating as seriously as she does everything else, but does not quite get it. She pragmatically suggests activities that are too sexual.

(Source: KADOKAWA)