No children are not always this annoying. There is one BIG thing you must learn in the busienss of entertaining children and that thing is crowd control. You must learn how to control your audience or they will be all over you and everything you have! Learn to control the kids, and you will go further.
Asking the children to stand up was a big mistake. You want the kids sto stay seated the whole time. Sometimes, it is necessary to ask the parents for a little help. But you should learn to handle most of the problems yourself. Never argue with a kid, or "call him out" you will never win. Also, never choose a helper that is loud and annoying...if you do, you will regret it. There is no use in rewarding a heckler.
Remeber...kids like to do the opposite of what you say, so don't get bossy or you will go nowhere.