This is actually an interesting issue - what is optimal? The tester who tested DD said between 6-8 years old was best. I know others have opined 8-9 is better. I actually felt when all was said and done that 8 was rather LATE for having DD tested, especially for gifted girls, who tend to start to "hide" by age 9 (perhaps others can quote more specifics, but Linda Silverman has discussed this, #4):
http://www.gifteddevelopment.com/What_is_Gifted/learned.htm.Is this only true for girls, though?
Also, by 8, DD definitely "lost" time in school. I would like to learn from this and see if I can avoid this with younger DS. As 22B said, kids need to learn at their own pace. The "lockstep learning plan" used by many schools is not good for either of my DC, and probably not for many of the children discussed on this board.
