Tensei shitara Dainana Ouji Datta node, Kimama ni Majutsu wo Kiwamemasu

Prince Lloyd wasn't always a prince... in fact, his previous life is one he remembers perfectly: he was a sorcerer, of sorts. So when he was forced to reincarnate, he decided to continue his studies, prince of the realm or no! But his new life has its own sets of challenges... including being a 10-year-old! What's the 7th prince/sorcerer to do?!

(Source: Kodansha USA)