In the United States, you are considered an adult at 18 years old. With age comes a multitude of other privileges. You can drive at 16 with a proper driver's license, have sex legally at 17, vote and buy cigarettes at 18, and buy and consume alcohol at 21. Although there is an age limit that is not set in stone. In the legal system, you can be considered an adult at 18 and be judged as such. Whether you can be tried as an adult depends on many circumstances. If the individual has committed a serious crime, such as armed robbery, rape, or murder, then he or she can be tried as an adult. If the individual was tried as an adult in a previous case, he or she will continue to do so indefinitely. The prosecutor or judge may have a choice in how they want the individual to be tried. Maturity level can play a role. There are so many conditions that can lead to over-trying as an adult. This is where science comes in. Cognitive development, to be more exact. Cognitive development is the study of the ability to think and understand. It's a field of neuro...