Oh, I was suggesting going in person to the math departments! 
I think it is the case that exceptional mathematical talent does tend to emerge early.
But I also think it is sustainable.
If you are on this forum, chzbrgr, perhaps you have children in high school, or just recently in college?
If–like me–you are not getting much sleep during your children’s high school years, wait until you can catch up on your sleep. You will find that you get a remarkable increase in intellectual clarity.