The law seems to agree. California’s legal ages laws, for instance, establish that an individual reaches the “age of majority,” or the age at which an individual is legally considered an adult, when he or she reaches 18 years of age.
Legally, the term child may refer to anyone below the age of majority or some other age limit. The United Nations Convention on the Rights of the Child defines child as “a human being below the age of 18 years unless under the law applicable to the child, majority is attained earlier”.
A tween (pre-teen) is a child who’s between the stages of childhood and adolescence. Some tweens may be in this stage until they’re 13 years old. Regardless of the exact age, tweens all have one thing in common at this stage of life: they experience significant changes as they approach puberty.