Should I say "I'm 24 year old" OR "I'm 24 years old"?

[Si2007]

Dear Friends,
Somebody please help.

I remember my teacher told me when I was a student that I should say :" I am 24 year old" not " I am 24 Years old" .
He was always stressing that the word "year" should come in singular not in plural because here "24 year" is an adjective and adjectives never come in plural.
However, I used to see some written text thereafter showing "years" in plural for the same structure.

Please advise which is correct ??

Thanks for your valuable help.

Sherif

[Yankee]

Hi Sherif

These are all correct:

1. "I am a 24-year-old."
2. "I am a 24-year-old woman."
3. "I am 24 years old."

In sentence 1, "24-year-old" basically functions as (replaces) a singular noun.

In sentence 2, "24-year-old" basically functions as an adjective describing the singular noun "woman".

In sentence 3, "24" modifies the plural noun "years". (Notice that there is no indefinite article "a" used in that sentence.)
.

[Si2007]

This is very helpful!
Thanks a lot Amy.