Nasa is probably honestly beyond high school level knowledge with his super-genius status (I mean, he seems to be capable of university-level mathematics and calculus, programming, etc...), and Tsukasa has far more real-world experience than any silly high school could teach her; the only thing she definitely has no experience in is love and romance, which has only started accumulating as of marrying Nasa, so her experience with it is the same as Nasa's. Which explains their level of innocence.I need someone to remind me why they aren't going to high school