when describing age

Question

I recently came across this sentence in my English class and found it a little weird.

It said, "A girl of about nine years old had recently described ..."

Often I hear people say "a girl about nine years old" or "a nine year old girl" or in such structures alike. I don't find the "someone of something" so weird, but I don't think this expression is employed so much, I typed the exact phrase on Google, but came up with no uses.

As far as I know, people say things like "a man of experience", or "a man of 40 years of experience", but I've never heard such thing as "a man of 40 years old". It sounds really strange to me.

Is this expression right?

Answer 1

It's merging two ways to describe age, so it is not right.

A girl of about nine years had recently described...

This is a recognised way to denote age, though it's less used in every day conversation.

A girl, about nine years old, had recently described...

This is probably more common. Actually, most common would be:

A nine-year-old girl had recently described...

But that doesn't allow you to indicate uncertainty or approximation as easily. You can say:

A roughly nine-year-old girl...

That, however, comes across as clunky, inelegant.