at or of one’s age

Question

When I was a student ______ your age, I tried out for our school volleyball team.

of or at to fill in the blank?

Our teacher told us that “at” is incorrect. He said “at one’s age” should only be used as an adverbial modifier, like in

At your age, you should be able to work out your own future.

While “of one’s age” can be used as a postpositive attributive , like in the first sentense or in

Boys (of) your age ought to be sweethearting.

Or as a predicative like in

When I was (of) your age, I worked on the farm.

I wonder what our teacher said is correct. I just feel so natural to say at in all these contexts.

Answer 1

This is a fun question, because it reveals something about English that I never noticed, even after speaking it for 42 years or so.

Your professor is partially correct, but there's more to it. "At your age" is a set phrase with a negative connotation that almost always means, "...you should/shouldn't be doing the thing I'm about to mention or just mentioned." Another common construction using "at" is "at the age of X," e.g.:

He left home at the age of 16.

("At the tender age of...", indicating youthful innocence, is a common cliche.) "At the age of" feels like formal or written English, whereas "at your age" is casual speech (and maybe a little dated). You can also omit "the age of" and just say, "He left home at 16," wherever it would be unambiguous to do so.

Now, for your first sentence:

When I was a student ______ your age, I tried out for our school volleyball team.

Neither "of" nor "at" sounds remotely natural to me. The best words to put in the blank would be nothing at all ("When I was a student your age..." is perfectly natural English) or "about."

"Boys of your age" and "boys your age" are both acceptable. However, "When I was of your age" is not. I'm having trouble figuring out what the rule is, though. Anyone?

Finally, I've never heard "sweetheart" used as a verb, but it sounds so nice I wonder if you're quoting a famous line.

Answer 2

Of your age sounds more formal (and is what lept to mind before I had even fully read the question), but I can see a case for both, at least in a colloquial context.

As for why, my guess would be at least partially the focus of conversation. That said, I must agree with @mamster in that omitting of in this instance sounds the most natural (similar to your other examples).

The Person You're Addressing Is Not The Direct Focus

• When [I] was a student (of) your age, [I] tried out for our school volleyball team.

• [Boys] (of) your age ought to be sweethearting.

• When [I] was (of) your age, [I] worked on the farm.

• [Children] (of) your age spend too much time on the internet.

The Person You're Addressing Is The Direct Focus

• At your age, [you] should be able to work out your own future.

• I can't believe [you've] never had a job - -- not at your age.