Little Ah-ha . . .
We learn "line upon line, precept on precept." Right?
A very simple and true principle when you think about it. After all, can you understand Calculus without basic math or algebra? Can you understand great literature without knowing how to read?
The ah-ha -- there isn't a speed limit on that. If someone is capable of learning and understanding math principles, if they have the opportunity, work ethic, and support to do it, they could race through a whole lot of math. Likewise with anything else.
The more time and effort you put into something, the more "lines" and "precepts" you can keep adding to that.
Almost 6 years ago I was at my first homeschool conference, and the keynote speaker mentioned that we have a choice for the the next 5 years. We can keep doing what we're doing and stay the same that we are, progressing as we have been. OR we could decide a direction, set goals, and progress in huge amounts, all in the same 5 years.
Incredible the difference a few years can make. (Pondering more about that now. Feel free to do the same.)