I took calculus in High School, it was a dual credit course with a state university. I got credit at the university for the first semester of calculus (which was taught over the entire year in High School, so at a slower pace, but also allowed the High School class to spend more time on review in the first month or so, compared to college courses which basically dive right in). We took the same exams as the university course.

I felt I was prepared for 2nd semester calculus when I took that as my first math course in college.

That's a totally different argument. I mean, did arithmetic "algebra" prepare you for abstract algebra or even linear algebra in college?

Actually, yes. The rules for manipulating 'expressions' with 'variables' in school algebra describe what are called "free objects" over some set of "generators". The whole setting generalizes pretty well.