[Metroidpreg]

This is an interesting topic.
I personally think Puberty refers the chemical process, we all went thru. It cannot be used to refer to the moment one starts discovering about sex. I think it's too broad of a generalization.
If that was the case then i hit puberty when i was 6, everyone experiences that "where babies comes from" and playing "doctor" to discover it's own and other's body.
I too started with childbirth thanks to a book and moved to mpreg much later due to the will to experience it on my own.
To put it very simply i started enjoying pregnant and birth related content well before i reached puberty and could orgasm.