I don't know. I guess it depends on what your definition of pretend play is. My daughter (the younger one) started pretending to be a kitty at around 1½-years-old. It branched out from there. Now she is a little over 2 and she pretend plays quite a bit. She has her dolls verbally interact with each-other. She role-plays as a mommy and such. She still pretends to be a cat. She sometimes even pretends to play dead (Complete with lolling tongue... we're not sure where she even picked up on that one.

) I'm not sure how much of it is due to her unique personality, or how much of it is due to having an older sister. I don't remember my older daughter getting so in depth with the pretend play at such a young age. But Aurora does a lot of things earlier than her sister did. It could be in her nature, or it could be from her environment. I guess I'll never know.
I will say that perhaps her early pretend play was linked to early verbalization? Aurora understands and can express many concepts beyond what people expect from a child her age. I was the same way... though my memory is fuzzy on when exactly I started clearly expressing all the ideas floating around in my head. I remember thoughts from my toddler years more than I do specific interactions.