"24 years old or 24 year old"? [closed]

I'm wondering if there should be an "s" when telling about ages. I have heard from my native English friend says "I'm 24 year old" is it correct?

Solution 1:

When describing someone by their age, you would drop the 's'. This is because when you express a unit of measurement (in this case time, or age) as an adjective, it become singular.

• The 20-year-old student you're referring to was last seen in the park.
• I am a 24-year-old college graduate.

However, when someone is stating their age, you would attach an 's'.
This occurs because when a unit of measurement is used as a noun, it becomes plural.

• He is 32 years old.
  
• I am 40 years old.

I think anyway, hope this helps some. :)