This gives me some hope! Thank you.
I guess I need a little advice on what course will come next also. DS1 has done the AoPS series from Alg 1 - Calc. He is planning to take the AP BC exam this year, and assuming he scores well, will get credit for Calc 1 and 2. He is most likely headed for a math degree, but at age 15, everything is a bit up in the air. So, seeing a math degree as a high probability for him, I want to make sure that whatever family decisions we make, he is moving steadily ahead in math.