What is the gambling age?

Many people are interested in the question "what is the gambling age". That's simple - it's 21. However, in addition to legal issues, the gambling age doesn't have anything to do with the question whether you should gamble or not. In case of gambling, or to be more specific, in case of Texas Hold'em poker, it doesn't matter if you're 21 or 58. It really doesn't. What matters are: