childly

Example:After years of practice, he had finally become mature in his artistic skills.

Definition:Having reached maturity; developed to full physical, mental, or emotional capability or capacity

Example:He acted like such a grown-up, carefully considering the consequences of his actions.

Definition:A full-grown adult; no longer a child, or behaving as a child would

Example:Only adults were allowed to enter the area with restricted access.

Definition:Of full age; no longer a minor or in the early parts of life; mature, of full age, of adult years