I was told when I was 5 and my dog died that it didn't get to go to Heaven. I thought that was massively unfair at that age.^ I can't remember a time when I believed the assertion that humans had an afterlife and (other) animals didn't. It's always seemed self-evidently false, given that there's no aspect of the human psyche that doesn't have a counterpart elsewhere in the animal kingdom.
Now I know the whole thing is a delusion shared by far too many people.
Still, if there was, I'd rather be with my pets than most people I know.