Eiyuu-ou, Bu wo Kiwameru Tame Tenseisu: Soshite, Sekai Saikyou no Minarai Kishi♀

After living a life devoted to serving his country and people, Inglis’ one wish to be free of a king’s burden and to train was actually heard, but as a beautiful girl! Reborn in the far future as a daughter to renowned knights, Inglis can now focus on mastering the martial arts. A wish has been granted, and Inglis will be on the front lines fulfilling the dream of becoming the strongest knight.
(Source: Crunchyroll)