The 8th Son? Are You Kidding Me?

25 year old Shingo Ichinomiya falls asleep while making dinner after a day at his office job. He awakens in the body of 5 year old Wendelin Von Benno Baumeister. As the 8th son in the Baumeister family, his future seems bleak, until he discovers that he has the rare gift to become a powerful magician. Based on a Light Novel by "Y.A."