Update:
I pulled DD over to the computer a few minutes ago, and showed her the IQ bell curve. It had a little picture of Einstein over to the right. I explained that I was showing this curve so I could answer her question about her IQ. I pointed out where the 100 is and how a bell curve worked. Then I pointed to her general area. She got this big smile and a new awareness crossed her face. I hope that she understands - really takes it in.