I took a combined calc 1 and calc 2 class in college after taking a calculus class covering AP calculus AB and BC in high school, which I think was a nice balance probably (my school didn't let you skip it completely). The refresher was nice (it had been a year since I took calculus in hs), but I might have been fine doing multivariable regardless. It all made a _lot_ more sense for me in college, I'm not sure if it was maturity or what that made it easier for me, but the difference was shocking.