I've been taking skating lessons in a group for a couple months. They check your skills and then group by ability. They don't aim for perfection when checking skills --- they just want you to be able to do something reasonably reliably.
The teacher will show us how to do something and then give each student a bit of one-on-one time. Then she'll say, "Okay, who wants to learn a new skill?"
If you want to learn the new thing, you go listen/try. If you're not ready, you don't. You don't have to learn everything in a pre-ordained order. If you want to learn something else, you can ask her and she'll show you and you can try. It's amazing. I have never, ever felt so perfectly challenged in a class.
Too bad school can't be like this...taught by people who have a deep understanding of the subject who recognize that different people learn in different ways and at different rates.
Val