I've only read the first page, but wanted to add my 2 cents.

I have been in that situation, and found a solution other than skipping, but it probably isn't something you can do. I think your child being happy and challenged is more important than you not wanting her to grow up too soon. Every mother thinks their child is growing up too soon. Reading sixth grade stuff doesn't make a five year old eleven, they're just a five year old reading long complicated sentences or doing long division or whatever.

But look at it this way - given the choice between a short childhood and a happy childhood, which would you choose?