Playing blackjack at 18 in California is generally legal, with a few exceptions. In most cases, playing blackjack is considered an adult activity and is not subject to the same regulations as gambling activities that are restricted to those over 21 years of age. However, there are a few exceptions to this general rule. For example, playing blackjack in a casino setting (where you may be able to win money) is generally considered an adult activity and is not subject to the same regulations as gambling activities that are restricted to those over 21 years of age.
In addition, some state statutes prohibit individuals under the age of 21 from participating in certain types of gambling activities, such as blackjack. Therefore, it is important to check the specific statute that applies to your situation before playing blackjack.
