I had a humbling experience last year when I browsed the available courses until I found one that only contained math I'm already familiar with and I had to go all the way back to fourth year elementary school. :/
What I'm trying to say is that you've made a good decision by jumping way back. Once thing I realized pretty quickly is that to do well in math, you need to know the prior content pretty well. And for the next thing, the current content pretty. And so on. If you can stay on top of it, it 's a lot less challenging (and more interesting).