A child who doesn’t live much with older people (it is bad for children to live much among older people), a child left to itself will sleep spontaneously whatever it may be doing, the moment it needs to sleep. Only, when children are used to living with older people, well, they catch all the habits of the grown-ups. Specially when they are told: “Oh! you can’t do this because you are too young! When you are older, you can do it. You can’t eat this because you are small, when you are bigger you will be able to eat it. At this particular time you must go to bed because you are young….” So, naturally, they have that idea that they must grow up at any cost or at least look grown-up!
Ref: Questions and Answers 1953