In our society, many tacitly agree that it's best to grow up quickly. Start reading at three, music lessons at four, specialize in a sport by five, the solid beginnings of a career track in place by mid grade school. It's a race to success. Whether it works is debatable.
Here's an alternate theory: Kids should grow up slowly. They should live in a world of magical imagination and play until they are, say, eight, and then gradually start into more adult-like, disciplined skills like reading and writing and math and responsibility. And even then, they should be treated like kids. They should be protected, as much and as long as possible, from the complexities and brutalities of the adult world. They should, in other words, be given ample time to have a fully realized childhood, in order to move fully and confidently on to the next stage. Serve no wine before its time, as it were.
That's sort of the idea behind Waldorf education. If you've got a young kid, you might want to consider it.