According to AP Style, you don’t have to write your exact age in figures everywhere. There are some specific areas in which you can mention your age. For example, you can mention your age in figures in your profiles, forms such as admission or application forms, eulogy, etc.
However, if someone says that ‘I can’t work much, I am too old’ or ‘a veteran of two world wars’, then there is no need to mention the exact age. The person’s age is relevant in this manner.
If you want to refer your age at any place, you should use figures instead of spell it out. For example,
1. My mother has a 20-years-old chinese bowl.
2. My sister is 23 years old.
3. They both are now 10 years old.
Note: In the first example, I used hyphens for chinese bowl’s age because it is expressed as adjective and used before noun.
Important Point to Remember
If you say,
‘I am in my 20s.’
Then, you should remember that there is no need to use apostrophe between ‘20’ ans ‘s’.
• She was so beautiful and energetic in her 30s.