Lessons which expect children to pay attention to lots of teacher direction and which have little space for free play, experimentation and creativity are difficult for many young children. Longer programs should have a combination of free play time with lots of choices and variety, as well a few structured events like circle or snack time. Consider group size and level of stimulation. Most young children do better in smaller groups, and the younger the child, the smaller the group should be. Groups of six to ten are much easier for children than groups of 20 to 30.
More kids means more adults and more noise and activity.
Again, it is important to look at your child's individual temperament. A few children seem to thrive in very stimulating environments, but most do better with a moderate amount of stimulation. Think about the consistency of the group. One of the benefits for children of participating in groups is learning about other people and how to relate to them. If a child is in an ever-changing group, he spends all of his time orienting himself to each particular group and less time interacting and building meaningful relationships.