12-13 years of are is very young to start gambling in my opinion. In my country you need to be atleast 18. I remember when being 16 that I really wanted to go a casino, but even with my parents it wasn't possible. The only thing I could do was play scratch cards at home. With hindsight it was probably good that I couldn't go gambling because the risk of getting addicted is much higher in younger ages. If the young gamblers where supervised by their experienced parents than it might be okay.
12-13 years of age was too young to be engage in gambling, at this age a child shouldn't be involved in this kind of game, they must enjoy playing at the field, more on strenght kind of game. Actually I guess at the teenage years of a child or youth they can be taught about gambling but don't encourage them to join because it was so risky for them to enjoy gambling. I am worrying about the possible effects in emotional and mental aspect that a gambling may bring.