So literal

The kids were taking turns riding a "horse" (one of those on a frame with springs) at nana and pop's house. Doug and Andy kept putting on pretend hats and saying they were cowboys. Andy was even going so far as to fake cough for the horse and give it medicine to make it feel better.

They handed Josie a pretend hat.
Andy: Josie you're a cowboy.
Josie: I a girl.
Mommy: So you can be a cowgirl instead.
Josie: I not a cow.