Mama wa Shougaku 4 Nensei

Fourth-grader Natsumi Mizuki's parents have left for London. Izumi, her aunt, moves in with her. Izumi doesn't have time for a baby that materializes on Natsumi's first night alone because she is a budding manga writer attempting to land her big break. Mirai is the name of the infant, and Natsumi is her mother, although she is 15 years older. Mirai had returned to the past in some way. The young Natsumi is now responsible for raising Mirai while attempting to prevent her life in the fourth grade from disintegrating and keep Mirai-chan a secret from everyone. Izumi's assistance is doubtful, and she also possesses some futuristic infant care technology.