If she was impressed with The Hurried Child, she might be interested in reading this, by the same author: http://www.hoagiesgifted.org/elkind.htm

And you might note that it is not appropriate to hold a child back from learning because of asynchronous development. A baby voice? Come on. frown Besides, gifted kids who are not challenged will (of course) develop resistance to doing menial tasks and following instructions.