This graph is from Harvard’s Center on Developing Children.
More happens between 4-5 in terms of executive function brain growth than in all of the rest of life put together. It’s pretty clear where we should apply our efforts in enlarging the creative capacity of a person.
The full article is at https://developingchild.harvard.edu/resources/building-the-brains-air-traffic-control-system-how-early-experiences-shape-the-development-of-executive-function/