Points to consider:
Emotional maturity-This leans toward the idea that if you can keep their childhood as normal as possible, the thinking nowadays is to do so. If your child is demanding to advance, then take that as a cue to help accelerate if that works for your family. It is like a sliding scale where you are constantly weighing and monitoring what is going on. In medicine, medical professionals all always saying that they can't predict for sure what will happen next, so don't be afraid to change the educational plan to meet what happens next.
Goals--Some families need for the children to get through college early for whatever reason. Some people don't want their child in college early, they just don't want their child's brain wasted before then.
How much mental stimulation does your child need? Who can provide it? When and how? What is the cost and who carries the cost? Schools do not see what is going on at home and how the child is voracious and the parents never get a free minute.
Personally, I love the idea of acceleration in theory, in that if I can get my hands on knowledge that is new to me and so interesting, I am much happier with life overall. I can choose to study X,Y,Z, in college and post-grad, but it would have been nice to have been intensely studying A through W before then.
Hope it helps. Good Luck.
