I guess the right age is 21 to gamble because they're more matured but it dosn't make sense because its easy to other youngsters to enter in any sites however its too dangerous to others for being addictive of doing it and its so easy for 18 below to enter gambling in sites because of verification they just tell that they're 18 and tadah they are allowed to open any sites so maybe make it hard about the security.
At 18, most people don't go to work or earn money yet. Most of them live off their parents and receive pocket money from their parents. That is, the majority do not have free access to money.
It is very easy to lose at a casino, and it is also very easy to feel the need to win back. So you need to find more money in order to win back, because then you can return it. The younger we are, the easier we get into debt without understanding the risks for which our parents pay later.