Have you known that there is an age restriction in gambling? But it is varied among the countries in the world. I have just checked in wikipedia that commonly someone can play gambling starting from the age of 15/16/18/19/20/21 years. It depends on where he lives, every country may have different regulation related to the age restriction. Below I classify some countries based on the age restriction:
Age 5: Malawi (Casino)
Search about this one and surprised that it's true. It makes me realize that some games in arcades imitates gambling as well. it's all fun and games for the kids but we know it's where gambling starts. Haven't found the reasons about this '5 year old restriction" but if a 5 year old is gambling, they won't know it's gambling, they will be happy winning, they will be sad when losing. And they will want more.
Gambling requires a great deal of responsibility that's why most of the countries use 18-21 as their minimum age to gamble. I hope kids who gamble can still control themselves to stop when they grow up.