My son was 8 when we went to our first reptile seminar, he was more patient than I. I would divide the classes by subject. I think you could do 3+ hours on snakes alone! I guess making them topic specific, have people sign up for "Enclosure Building and Housing Needs" and what type of pet they have/want. "Choosing the Right Pet For You." I really don't think you can cover all of the topics in one class- a series of offerings might work and be more manageable.