Youjo Shachou

The president of Mujina Company, Najimu Mujina, isn't an adult, nor does she possess a genius intellect; she's a very ordinary 5-year-old girl. Followed by her indulgent and talented secretary, an office clerk of unknown nationality, and an employee who plays the straight man, the president charges into the world every day.

(Source: Kadokawa, translated)