young/old for one's years

: being in the first or an early stage of life, growth, or development

: junior

: of an early, tender, or desirable age for use as food or drink

: young persons : youth

: immature offspring

: a single recently born or hatched animal

: dating from the remote past : ancient

: persisting from an earlier time

: of long standing

: one of a specified age

: old or earlier time

: the period of about 365¹/₄ solar days required for one revolution of the earth around the sun

: the time required for the apparent sun to return to an arbitrary fixed or moving reference point in the sky

: the time in which a planet completes a revolution about the sun