A more thorough explanation:

The legal age, also known as the age of legal majority, is the age at which a person becomes an adult in the eyes of the law. This means they gain control over their own actions and affairs and become responsible for the decisions they make. The legal age is set by state law and can differ from state to state, but it is usually 18 years old.

Once a person reaches the legal age of their state, they may enter into legally enforceable agreements. However, minors do not have the legal capacity to enter into a binding contract. For example, a 17-year-old cannot sign a lease for an apartment. But, an agreement made while a person was a minor may be ratified once they reach the age of legal majority so that the agreement becomes valid and binding.

Those past the age of legal majority are usually tried as adults when charged with crimes. This means that if a 19-year-old commits a crime, they will be tried in adult court and face adult consequences. However, minors may obtain the status of legal adulthood before reaching the legal age of majority if they are granted a court order for emancipation, or if they meet statutorily defined exceptions such as getting married as a minor or obtaining certain educational degrees.

The legal age is separate from legal age of license. A legal age of license is the minimum age a person must reach in order to legally participate in certain activities, such as drinking alcohol, voting, or driving. Legal ages of license vary by the activity and the jurisdiction, and can, but do not have to, match the age of legal majority. For example, the legal age of license for driving in most states is 16, but the legal age of majority is 18.

Overall, the legal age is an important milestone in a person's life as it marks the transition from childhood to adulthood in the eyes of the law.