Is "vieil homme" or "homme vieil" correct? I think it is the former because it describes age.

Yes, you are correct! The correct phrase is "vieil homme," which means "old man" in French. In French, adjectives generally come after the noun they modify. However, there are a few exceptions to this rule, and age is one of them. When expressing age or size, the adjective generally comes before the noun.

To get the answer to your question, you can consult a French grammar guide or a reputable language resource like a dictionary or language learning website. These resources will provide you with the correct grammar rules for adjective placement in French. Additionally, you can also consult with a language teacher or a native speaker to get confirmation and clarify any doubts you may have.