It sounds like you might be smarter than the vast majority of highschool students to which the GP comment was aimed at.
The problem is, the math and civics classes already present in highschool should be adequate, it's just that many of the students don't take it seriously and try to learn - an extra year isn't going to fix that.
The problem is, the math and civics classes already present in highschool should be adequate, it's just that many of the students don't take it seriously and try to learn - an extra year isn't going to fix that.