I do not mean to discount this interesting iota, however, I had a similar realization when I was 7; whether it coinciding with learning of the Copernicus principle is merit or raw luck notwithstanding, I saw my siblings as none other than another family in another house: all others would view me, and us, as neighbors, and we are all side-characters in each others story.
That thought is "sonder" - although it differs from what you describe, it has some parallels.
I happen to be with Sagan on this one, although these ideas certainly are not mutually exclusive; in fact they are complimentary.
Consciousness is an innate emergent phenomenon that happens when you combine basic memory/context, recall, the collective evolutionary unconscious, and so many magnitudes of neurons.
In fact, he even gives dogs (and to some degree, cats) the exactly same specific pedigree of obviously being self-aware/conscious, yet commanding the traits that align with the most basic tenants of "religion": your dog thinks you are a fucking god.
Congratulations!
You just destroyed painters' jobs.
What's next? Take a man's horse! why dont ya?