Not everyone has a friend who will teach you how to place bets, many of us learned this ourselves, and perhaps long before online casinos appeared, and I don’t even remember knowing that there was a ban on playing under 18. And I gained experience myself, tried figured out the rules myself, tried to understand what these fors or handicaps mean. There is no big difference in how we get experience, what matters more is how good you are at gambling and even if you are taught all the basic rules that cannot be broken in gambling, I am sure every player will want to try to do this at least once, because their experience is priceless.
Everyone can learn gambling without needing the help of explanations from other people, they can learn it themselves by betting regularly with low bets and of course they will understand the features of the game and some basic strategies for finding opportunities to win. But the main reason for determining the age limit of 18 years is to prevent those who are still of educational age from being affected by the impact of gambling and those who are still financially dependent on giving money from their parents. So one of the main factors why age limits in gambling need to be set and even some countries that legalize gambling also have age limit requirements for gambling.
Not everyone who is 18+ can gamble, because not all wants to gamble or believe in gambling. But, from the settings of gambling, it's not hard to learn. Especially games like slot. Sport gambling have odds which can be confusing on new players and would require an experienced player to teach the new gambler, what those 'overs' mean. However, once one turns 18 they'll want to try out all those things he was openly told not to do, as an underaged person. Which makes many of them not to seek help from any expert. Out of their curiosity and naiveness, most of them also get into trouble. I think that gambling was made 18+ for a reason, which doesn't mean that once a person hits the age, that he should start gambling immediately. It sounds as though the person has been waiting all his years to start gambling at 18. Such mentality can lead to problematic gambling.