C is always a challenge. Stick with it and it will get there.

I downloaded an app on my cell phone. It's called JustinGuitar One Minute - you take two cords and hit start - you try to see how many cord changes you can do in one minute. It's a good exercise to focus on your cord changes. I think the app is free.

I do wish they would include tabs with the lessons so you can start to get familiar with reading guitar tabs.