Overall, it is certain that someone who is less than 18 years old will not be allowed to engage in gambling, none other than because it is an age where a person has not yet entered the phase of maturity in himself which makes it difficult for him to make considerations to get the best decision according to the situation and conditions. But if we talk about gambling then I think someone who has entered the age of over 20 years can still have a childish nature that makes it difficult for them to balance themselves, so I can't say that all people who have passed 18 years are those who are really allowed to engage in gambling, in the end it depends on the person too because there are quite a lot of factors that make them not enter the phase of maturity even though they have exceeded the age of 18 years. On the other hand for other issues about KYC, in my opinion someone who is still under the age of 18 will not experience any problems if for example they are involved in a casino that does not make KYC a condition of involvement, because lately there are also quite a lot of casinos that appear without making KYC a condition for involvement.
This is all because teenager whose age cannot yet be called an adult has an attitude that still tends to be unstable and they have no way of controlling themselves in an activity under certain conditions, gambling is quite risky activity and self-control is very important.
Apart from that, they also don't have the personal identity that all adults usually have and the average gambling place requires all customers to enter when they already have personal identity and the same thing happens in online gambling because of KYC.
Moreover, most of the children or teenagers are still studying or going to school and when they gamble it means they are delaying their studies or completing their education.
It just that right now, age will never guarantee person maturity and age will not guarantee person mindset can be better, apart from that regarding KYC, as currently almost all gambling sites use it, there are also some that fake KYC.
Everything has become much easier and what can stop it all is the gambling site itself, such as implementing facial scans for KYC completion by matching the personal identity used, but I sure not all gamblers will agree to this.