We do a disservice to students in the US by treating Algebra/Calc as advanced math. Typically, American schools judge student math aptitude prior to algebra based on rote memorization of multiplication tables. Potentially with the added benefit of more rote memorization problems if one is in the honors curriculum. Aptitude for this type of problem does not directly translate into aptitude for higher math.
There is nothing particularly advanced about Algebra or Calculus. At most, it's a question of how much time one is willing and able to put into the subject. The fact that most American students do not exit high school with a functional knowledge of single variable calculus is purely an artifact of our curriculum priorities.