Why you drink until your 21?

In many countries, there are laws that prohibit the sale and consumption of alcohol to people under the age of 21. These laws are based on the idea that the brain is still developing until that age, and that underage drinking can have negative consequences on brain development, increase the risk of alcohol dependence later in life, and contribute to other health and social problems. The reasons behind these laws are complex and involve considerations of public health and safety.