Quoting MommyingWithGrace:" We did homeschool and my son is in public school now, sooooo..that should give you some indication of ... [snip!] ... knowledge. School will certainly expand their knowledge. My son learned more in school than he ever did with me teaching him."
If you look at other countries school systems there is learning before the age of 7 but they do not start school until this age. Children are allowed to play and simply be children. In their kindergarden it is more about learning about caring, love and respect. Reading is at their pace. In finland (top in education) there is no standartirized(sp?) test until the end of highschool, Their students surpass our students in every single grade. It has been proven through many studies that boys need plenty of outside/physical activity that this is a main reason that boys fail later in school. Up until age 7 in these countries they learn how to learn, they learn through hands on skills, playing and conversation.