Admire your ambition. Here something you may find helpful.

The broad topic is "Expert Performance". There are plenty of research on it. The predominant view is that regardless how talent is the kid, there requires ten year delibrated practice. Below, I attached one highly regarded article on this topic.

For a concert pianist, the practice time would be something like:

5-6 year old: 1 hours a day
6-8 year old: 2 hours a day
9-13 year old: 2 hours a day
15-18 year old: 3 hours a day
(more hours at competition, audition)

This is the ballpark effort you need to spend to get into top piano programs.

Delibrated practice needs to be under guidance of a great teacher. At age of 8, you definetely need to find a great teacher.

Click this link to see the article

The role of deliberate practice in the acquisition of expert performance