 Re: at the age of
By the age of and at the age of would both be correct, though with different meanings. Eg :
She was a millionaire by the age of 18 = before and at the age of 18.
She became a millionaire at the age of 18 = when she was 18.
It's the same difference as eg :
You must do it by Tuesday ( = you can do it on Monday if you want, or on Tuesday, but not Wednesday)
You must do it on Tuesday (no other day, before or after, is possible) |