It had been a while that we were asking N how old he is -- figure he was answering correct while he was around 2 1/2 --
So one day, when we were in the store, a lady came over and complimented how cute our little guy is and started to ask him his age, here goes:

"How old are you?"
Guess what he said?
"Fine!" --

He got confused by those two sentences -- How old are you (and) How are you :-) We explained to him and all laughed it out -- including him -- really has a sense of humor :-)

Now, if you ask him the same question "How old are you?"
He will answer say "Fine" with a naughty grim on his face...