immature vs age

immature is not a noun while age is a noun.

Word	Noun	Adjective	Verb	Adverb
immature	No	Yes	No	No
age	Yes	No	Yes	No

immature (noun)	age (noun)
	how long something has existed
	a time of life (usually defined in years) at which some particular qualification or power arises
	a late time of life
	an era of history having some distinctive feature
	a prolonged period of time

immature (adjective)	age (adjective)
not yet mature
characteristic of a lack of maturity
(used of living things especially persons) in an early period of life or development or growth
(of birds) not yet having developed feathers
not fully developed or mature; not ripe