I did educational shows in the past and they are a lot of fun!
Be prepared for some really great questions though, and trust me some of them will stump you.
My experience was that with most of the kids they were really interested in what a "cool pet" a snake or lizard would make. They did not understand, however, how long they live and that they are not always welcomed by parents or landlords.
I could send you some of the information I used in shows and some ideas of what the kids wanted if you are interested.
If you have any snake shed skins take them along the kids can at least touch that if they cannot touch the reptiles.