I dont really think it will have a very huge impact as, in my experience, the seven first years of school are only importang fof laying the first brick. informationwise it is the least important of them all. I for example did terrible those first seven years, having been born in January and all. Mediocre the next five and amazing this year.
I dont think the development of the brain have too much to say for your success later I woukd say: good choises (for example choise of school and classes), ambitions and the will to work hard or the lack of need for hard work. some are more lucky than others.
There are too many variables when I think of it, you parents, your friends, you neighbourhood, you school, you teacher and i could go on and on and on and...