Thanks so much for all the great advice!!!
I am definatly taking it to heart...
try not to get bogged down in answering too many "what if" scenarios from new students, ask them to leave it for beer waza time.
I have learned a good technique dealing with this. When the kids start asking stuff like, "Well what if its 100 ninjas, and they got a tank?" The response is, "Well I just press this invisible button on my wrist here, and it creates a force field and they can't touch me." Tbis will get a response anywhere from a credulous look to outright disbelief, and assertions that its impossible. The resoponse then is, "Well if you can use YOUR imagination to create these problems, then I can use MY imagination to solve them."
I will be teaching school-age children, so beer waza will have to be juice-box waza I think.
First class is scheduled for the 28th!