Stacy, we shouldn't compare Nani and Maggie. Nani is a Leonberger and is much more laid back than most puppies the same age. I have also been to other classes recently so I had an idea on what I needed to start with.
I'm sure if you find another class with fewer puppies that you will get more one on one time with the trainer and remember that the classes are more to train you how to train Maggie.
I know it can be hard, but if your angry or frustrated with Maggie she can feel it. Take a break and try again later when you've had a chance to calm down.