Infancy, minority, nonage denote the state or period of being under the age established by law for the attainment of one’s full civil rights and independence of guardianship.
Infancy is seldom used in this denotation outside of legal documents and court reports; in these it is especially likely to be chosen when reference is made to the condition or status of the person who is not of age.
Minority is widely used in general as well as in legal writing and is the word most often chosen when reference is made to the period or term of being under age.
Nonage is the equivalent of infancy and minority in their legal senses, but it is often distinguishable from them in its acquired connotations and by its greater susceptibility to literary and extended use. Nonage may suggest mere immaturity.
Not infrequently it suggests adolescence and its weaknesses and strengths and may be thought of as the opposite of dotage, or senility.