It depends on your perspective, if your kid shows interest on it then give them access into learning more about it. Otherwise, just give them some idea on what investing is.
That is no doubtfully is true. If kids show interest to certain things, then parents should pay attention to that and support them. But for me it is totally inacceptable when parents vision on situation is following: "my kids must learn about investment, because if they do it early, they will become rich quicker". Its parents wish to become rich with help of kids, not kids desire to be rich. Kids do want to be rich, but this is just a dream, a fantasy, not their life goal.
That's the thinking of the majority but for me, I've got a different perspective about that. While young, the more information and learning they take then they'd be having a lot of thought about things that the other kids aren't ready to discover.
But this depends on how's your parenting and it's also a valid thought of yours that they shouldn't get stuck into that thinking.
As for me, kids learning at an early stage about investing is a good one. It is going to teach them how to be wiser with money and the rest about getting rich, they'll discover that at their right ages.