A developmental process, independent of morphogenetic (shape) change, that is required for the olfactory nerve to attain its fully functional state. The olfactory nerve is a collection of sensory nerve rootlets that extend down from the olfactory bulb to the olfactory mucosa of the upper parts of the nasal cavity. This nerve conducts odor information to the brainstem. [ GOC:dph GOC:cls GOC:dgh GOC:jid http://purl.obolibrary.org/obo/go/references/0000021 ]