What is the noun and adjective in this sentence?and why?

noun: "Seventeen years old" NOUN a word (other than a pronoun) used to identify any of a class of people, places, or things (common noun), or to name a particular one of these (proper noun).

adjective: "is not old enough" Adjectives modify nouns and pronouns, giving a description or more information. An adjective clause is simply a group of words with a subject and a verb that provide a description.

In my day, they called this kind of use of "is" a linking verb.

years / is / old

all other words are adjectives to further describe the main parts of the sentence.

What is the verb of the main sentence?not Adjective clause

Verb: to vote Action word.