Jon Bloom has written a great thought provoking artilce on "Desiring God" website. He has identified how to be ready to answer your kids questions about the Bible and deals with some specific questions that are excellent. Every kids pastor and every parent should know this.
Here are the relevant questions:
How do we know the Bible is reliable? (Reliability)
Who decided what should be in the Bible? (Authority)
How do we know the Bible has no errors in it? (Inerrancy)
Who can understand the Bible? (Clarity)
Why do we need the Bible to know God? (Necessity)
Does the Bible tell us everything we need to know? (Sufficiency)
You owe it to yourself and those you teach to check out this article and wrestle with those questions. Kids need to know this and I know they are wondering about it.