I think it would have been theoretically possible, but obviously logistically difficult as I would have had to skip multiple classes in other fields to attend.
It's also not like I was particularly interested in mathematics at that point in my life. I essentially chose my field of study based on what I had the best grades in. Only during my studies, when the material actually became difficult, I started to be interested and engaged in the subject.
Schools in the US often offer different tracks within the same school but still offer different difficulty levels within them, including university level courses.
I think it would have been theoretically possible, but obviously logistically difficult as I would have had to skip multiple classes in other fields to attend.
It's also not like I was particularly interested in mathematics at that point in my life. I essentially chose my field of study based on what I had the best grades in. Only during my studies, when the material actually became difficult, I started to be interested and engaged in the subject.