Well said @renaissancedad. There are so many factors that go into where and how a child is placed. Both kids took placement tests before entering high school.
Sadly, my daughter’s math trajectory was set in elementary school when poor hiring choices by the school (teacher was eventually fired) led her to not being taught math at her level for more than a year. But since math is her super power, she eventually “caught” up and finished with one Calc class in h.s. and is doing well in college in a rigorous STEM program. My son has had a different experience and ended up “ahead” of his peers. But he’s working overtime this semester to maintain a B. Outcomes are often not as expected.