as of 15 minutes ago, i am 30 years old.
(31, if we do things the indian vay.)
either "vay", this birthday looms larger than even my 21st did.
either way, the suddenly foreign-sounding phrasing of my newly-attained chronological state ensnared me to the point where google was summoned. i needed it to explain what had unexpectedly stuck in my ears, and why that which was sticking felt so uncomfortable and strange.
et voila:
Why do we say "30 years old", but "a 30-year-old man"?
by Rich Alderson
This pattern goes all the way back to Old English (alias Anglo-Saxon). It's the same reason many of us say that someone is "5 foot 2" rather than "5 feet 2".
The source of the idiom is the old genitive plural, which did not end in -s, and did not contain a high front vowel to trigger umlaut ("foot" vs "feet"). When the ending was lost because of regular phonetic developments, the pattern remained the same, and it now seemed that the singular rather than the plural was in use.
Source: [Mark Israel, 'Miscellany: Why do we say "30 years old", but "a 30-year-old man"?', The alt.usage.english FAQ file,(line 6446), (29 Sept 1997)]
okay. if i try not to think about it too much, the afore-pasted blurb nearly removes my discomfort about new sounds and newer truths.
then again, if i try not to think about anything too much, that fixes EVERYTHING.