ma·ture [muh-toor, -tyoor, -choor, -chur] Show IPA adjective, -tur·er, -tur·est, verb, -tured, -tur·ing.
complete in natural growth or development, as plant and animal forms: a mature rose bush.
ripe, as fruit, or fully aged, as cheese or wine.
fully developed in body or mind, as a person: a mature woman.
pertaining to or characteristic of full development: a mature appearance; fruit with a mature softness.
completed, perfected, or elaborated in full by the mind: mature plans.
Your brain stops growing at 21 btw.