Electromagnetics is a pretty tough nut to crack, at least in my experience, because it's one of the most math-heavy things you'll see at a high-school/undergrad level. The good news is, though, that you wouldn't jump right into the vector calculus. It seems that you pretty much learn E&M by making a bunch of passes over it, each time making it more in-depth and getting more involved with the math. A first pass, like you would see in high school, might not use any calculus at all. The focus would just be to try to familiarize you with concepts like charge, current, electric and magnetic fields, etc. You'll probably mostly see specific examples where they give you the formula for the electric/magnetic field rather than any of the general laws governing charges currents and electromagnetic fields. Even after a high school level exposure, you'll probably see another college-level E&M course (probably based on single-variable calculus) before you jump into the real meat of the theory with vector calculus.
So don't worry about it too much. Third year physics and electrical engineering students have a hard enough time making sense of the vector calculus they see in their E&M courses that it would be ludicrous to try to make a vector calculus-based high school course for people who have just seen calculus for the first time.