People also tend not to believe me when I tell them I have never spent more than 30 min/day learning math, but I was always among the best and now I'm doing applied math in science.
The trick was that I started at the age of 6 and now I'm 31.
15 - 30 min a day, but every day.

Consistency is the key in life.
There are no shortcuts and the starting positions are not important, it can be fixed in just a few years of clever (not hard, but rather smart) work