Although you chose to post anonymously, I'm guessing that you live on one of the coasts, since you describe such high home prices. Please realize that this question has no "black and white" answer. I will tell you that every child is different, and learning takes place in many other ways besides strictly academics....If your child was to have a sibling, she is likely to gain in ways that no "formal test" could ever measure. You mention she likes company...having a sibling as she gets older would likely mean a "lifetime" of memories to share. I personally think that's a far more valuable experience than learning math facts in preschool, and it does sound to me as if she could be overstressed. Unless your daughter has a clear learning disability, in which case early remediation can be helpful, I don't see why you're emphasizing the academics at her age. It's a time to explore the world, and be a child. Even Ivy League colleges, if that's your goal, don't just want "straight A" students, but kids who are well-rounded, and who have passion about more than just bookwork. If she was my daughter, I'd sign her up for dance lessons instead of Kumon, and let her follow her own interests at this age...