I am wondering whether "at the age about" is correct usage or "at the age of about" is just more idiomatic. I would be grateful for any comments.
As a native English speaker, I see and hear:
at around the age of seven
much more frequently than
at the age about seven
at the age of about seven
Both seem weird to me. About is rarely used to describe age; usually around or approximately, in more formal cases.
at the age around seven
is almost never used, too.
at the age seven
is incorrect. In all except more formal cases, this is used most frequently:
for the children when they were around seven
Hope this helps clarify!