CR18 rims are pretty basic. If I was building wheels around 10sp hubs, I'd probably go a bit more quality. They are probably about as good as your stock rims.

For the class, I'd be real tempted to go with a flip-flop ss/fg hub out back, if you don't want to sink bigger money into upgrading your current wheelset.

If you really want to get ahead of things, find a spare wheel no-one will miss, disassemble it, and put it back together using any of a number of online how-to resources. You might not get it right, but you'll have a better understanding of the basics, even if the class teaches wheelbuilding a completely different way.