She is now in kindergarten and while her math skills are many years advanced and her reading skills are about 3 years advanced, we did not accelerate her due to having to jump through too many hoops and that she is not developmentally ready. She is not even top in her class now, as her handwriting is pretty sloppy (which even causes some answers to be wrong when she answers her Kumon math). We cringed when she told us that she answered her tests in school very, very fast as she was used to the Kumon method having a time limit. Unfortunately, that meant she finished REALLY fast, but overlooked a couple of questions and this incident confirms she is not mature enough to interact with older children.
I haven't had a chance to think enough about your overall question to provide an opinion. However, I disagree that overlooking questions means she's not mature enough to interact with older children. Lots of children skip questions, write sloppily, and race through work to get it over and done with. This is common in my DS6's 1st and 2nd grade classes. Also, many many gifted children are not top in their class, for many different reasons. Sloppy handwriting doesn't mean that she doesn't need the mental challenge of more advanced material.
I need to ponder your main question (accelerate, or slow down?) more before providing thoughts on that. There's a whole separate current thread on whether it's okay to coast or not, that might provide you some valuable thoughts on that topic.
