What is it about this expression?

[welldone]

Dear teachers,

I was reading newspaper the other day and saw a news like this:

"Four-year-old goes cruising

A boy drove his mother's car to a video store in the middle of the night, police said-and he's all of 4 years old. "

What does the underlined words mean? I have never seen this before. I guess it means something like "he's merely 4 years old". Is that right?

thanks a lot!

[Marylin]

Dear teachers,

I was reading newspaper the other day and saw a news like this:

"Four-year-old goes cruising

A boy drove his mother's car to a video store in the middle of the night, police said-and he's all of 4 years old. "

What does the underlined words mean? I have never seen this before. I guess it means something like "he's merely 4 years old". Is that right?

thanks a lot!

it's an expression and means no less than, at least.

[welldone]

The expression sounds weird to me.
. Thanks.

[Marylin]

The expression sounds weird to me.
. Thanks.

you're welcome.