The word adolescence has its origins from the Latin verb adolescere meaning “to grow” or “to grow to maturity.” Today, adolescence is used to describe the period of growth or transition between childhood and adulthood. As in most stages in life, there are no absolutes. It is generally agreed that adolescence begins with puberty. Puberty is the time when young bodies begin to physically mature and become capable of procreating. In Latin, puberty means “to grow hair.” Typically, this process begins somewhere between 11 and 13 with most children. But this is a generalization…every child is different.

While the beginning of puberty is relatively easy to decipher, the end of adolescence—the transition to adulthood—is much more difficult to pinpoint. Some consider adulthood to begin when legal “rites of passage” are met, such as legal drinking age, ability to vote, old enough to be drafted, etc. However, with this definition, the ages of these milestones differ: 18 to 21. Others belief that adulthood begins when physical maturity is reached. Still others consider it to be when the individual is “treated as an adult” by others offering respect and acknowledgement of decision making skills. When adolescents are asked when adulthood begins, they tend to focus on emotional independence from their families and assuming personal responsibility for their actions and their subsequent consequences. Parents, on the other hand, tend to focus on financial independence. Generally, it is accepted that
~puberty begins between11-13;
~early adolescence refers to those between 11 and 14 years old;
~middle adolescence refers to 15 to 17 year olds;
~late adolescence refers to those who are 18 and older.

In short, adolescence is more dynamic than static. Although many adolescents share similar characteristics and progress through the same stages, the speed of their progression and the length of each stage is as varied as each individual.

Reference

Rice, F.P., & Dolgin, K.G. (2008). The adolescent: Development, relationships, and culture (12th ed.). Boston: Pearson.