Adjective of Age

Eternal

Lasting forever

Enduring

Existing for a long time

Timeless

Does not change as the years go past

Abiding

Feeling or memory is one that you have had for a long time

Immortal

Living or lasting for ever

Perennial

Lasting a very long time, or happening repeatedly or all the time

Continuing

Keep on happening

Dateless

Not appearing to belong to any particular date

Deathless

Lasting for ever and never to be forgotten

Everlasting

Lasting for a long time