Coming of age
In the United States, teenagers are allowed to drive at 16 in all states except New Jersey, which requires drivers to be 17 and older, and sometimes receive the responsibility of owning their own car. Teenagers may drive at age 15 in Idaho and Montana. At 16, teenagers are also old enough to donate blood and work in most establishments. At 18 one is legally considered an adult and can vote and join the military. The legal age for purchasing and consuming alcohol and recreational marijuana, the latter of which is only legal in the District of Columbia, Colorado, Oregon, Washington, California, Hawaii, Massachusetts, Nevada, and Alaska, is 21. The legal age for purchasing and consuming tobacco products is 18 in most states; 19 in Alabama, Alaska and Utah; and 21 in California, New Jersey, Oregon, Hawaii and Maine. Multiple localities have also raised the minimum purchase age independent of state laws.
Maturity (psychological)
While older persons are generally perceived as more mature and to possess greater credibility, psychological maturity is not determined by one's age. However, for legal purposes, people are not considered psychologically mature enough to perform certain tasks (such as driving, consenting to sex, signing a binding contract or making medical decisions) until they have reached a certain age. In fact, judge Julian Mack, who helped create the juvenile court system in the United States, said that juvenile justice was based on the belief that young people do not always make good decisions because they are not mature, but this means that they can be reformed more easily than adults. However, the relationship between psychological maturity and age is a difficult one, and there has been much debate over methods of determining maturity, considering its subjective nature, relativity to the current environment and/or other factors, and especially regarding social issues such as religion, politics, culture, laws and etc.