come of age
to reach the age when you are an adult and are legally responsible for your behaviour

[TahlilGaran] Dictionary of Contemporary English ▲

come of age
[slightly formal]
1.
to reach the age when you are an adult and are legally responsible for your behaviour.
So what of all the fifty-thousand youngsters who come of age this spring? Who will they be voting for?

2.
something or someone that has come of age has reached full, successful, development.
After years of sophisticated mimicry, Japanese design has come of age.

[TahlilGaran] English Idioms Dictionary ▲

come of age
to be old enough to vote/marry/sign legal contracts etc.
When the members of our class came of age everyone started to vote.

[TahlilGaran] English Idioms Dictionary ▲

come of age
See: OF AGE.

[TahlilGaran] English Idioms Dictionary ▲