Writer, don't get me wrong. I do not agree with social promotion just to keep the kid progressing in grade levels without addressing the real issues of why he or she is not learning the material. But in most cases, simply repeating the same material that they didn't understand the first time...
I probably should have said "repeating a grade" rather than "holding back." But pushing ahead (starting early) is also not necessarily wrong. The important thing is being attuned to the particular child and what best meets his or her needs. I was "held back" from starting first grade because...
Different kids do better in different environments. Some excel with structure, others do better with less. Some cannot transition well from one subject to the next, expecially with the typical short timeframes in most elementary classes, but can focus on a single topic for long periods...