The age of majority is a term used to describe when a child becomes an adult in the eyes of the law, which for many things is 18 years old. This website describes some of what you are able to do now that you are 18.
Remember: turning 18 does not mean you have all the rights and privileges of an adult – some came earlier and some will come later. For example, in Idaho you were able to get a provisional driver’s license when you turned 15, but you can’t buy or consume alcohol until you turn 21.
