Eiyuuou, Bu wo Kiwameru Tame Tenseisu: Soshite, Sekai Saikyou no Minarai Kishi♀ Mini Anime

Synopsis

King Inglis, who lived for his country and people, strongly hoped to further temper my skills as a knight in his next life. The wish is heard by the goddess, who reincarnates the king into the far future, but in the form of a cute girl! However, it is declared at the age of six that she is incapable of being a knight, despite coming from a line of knights. (Source: MU, edited)