Synonyms young (having lived or existed for only a short time; not old): young children/animals/trees
teenage (between 13 and 19 of age): We have in fact two teenage children.
teen American informal (teenage): He is too old now for teen parties.
juvenile (relating to young people): Juvenile crime is increasing at a very high rate so far.
junior: The national junior swimming championship will also begin next month.
adolescent: Parents usually find it hard to understand their adolescent children.