A more thorough explanation:

Definition: Nonage refers to being a minor or under the age of legal adulthood. It can also refer to a period of immaturity or lack of experience.

Examples:

• At 17 years old, she was still in her nonage and couldn't vote or buy cigarettes.
• He was criticized for his nonage and lack of experience in the field.

The examples illustrate how nonage can refer to a person's age or level of experience. In the first example, the person is not yet legally an adult and is therefore in their nonage. In the second example, the person is being criticized for their lack of experience, which is also a form of nonage.