2 Year Old Fun

Even when Zack is sick and crabby and bossy he is so funny and cute. One of his things is he will NOT say how old he is. I'm pretty sure he knows he's 2 but I can't get him to tell me that. We were cuddling a few minutes ago and had the following conversation.

Me: Zack, how old are you?
Zack: My name Yack.
Me: No, how old are you?
Z: How many old is Eric?
Me: Eric is six, how old are you?
Z: My six.
Me: No you are not six. How old are you?
Silence
Me: (changing tactics) Zack, can you count to ten?
Z: One, two, thirteen...
This is unusual. Usually he says One, two, five, seven, eight, nine, ten. I didn't even know he knew 13.
Z: Momma, how old YOU?
Me: I'm 31
Z: My thirty-two. Mark is six.
Me: No, Mark is 4.
Mark: I'm almost FIVE!
Z: Momma, you thirty-eight. My one.

I gave up.