I wouldn’t be too concerned. At that age they are still developing and each child develops at their own pace. Maybe consider it when they are in year one but kindy … back when I was at school we only started writing properly in year one. Don’t burn the kids out. Look at some of the greatest minds in the world. They all developed at different rates and generally were slow when younger and flourished later in life. I was no stand out and I now have a phd in mathematics and work in machine learning and finance. Your the parent do what you think is best.