I think addiction is not a matter of age, but rather about how much a person is self-fulfilled in life and how satisfied they are with their life’s results. I doubt that someone would keep playing against themselves if everything in their life had worked out. Addiction, in my opinion, is the result of self-torment.
We usually say that once the person matures, he gets more control over his emotions and the chances of him being getting addictive should be less but it is seen that this does not happen usually. When a person gets mature, he also get settled in life and the money isn't a problem at that stage. The chances of doing excess gambling increases when you have the capital and the gambler should be careful not only to protect their money but at the same time limit certain funds for gambling and do not over position yourself. That's the only way one can save themselves from gambling addiction.