so it turns out that actually elves have a LOT of kids
like they are constantly getting pregnant
but the thing is they have a strategy more like frogs than humans, when an elf is pregnant he or she is just brewing a bunch of tiny little egglets in their womb for like a single month, then they go down to the Birthing Pool and a whole host of tiny little bug-like flying critters with wings just come popping out and they all fly away
and if they survive long enough then they will grow and molt and change and eventually they will stop growing new shells and start to look like what you think of as An Elf
but the thing is
these little critters are SO FUCKING TASTY, they are chock full of magic and they are so stupid, only a tiny fraction of them even survive to the first moult, never mind long enough to come wandering into the elf villages from out the wilderness once they have enough of a brain to start on language and society and all that
everything eats them, even elves, it’s perfectly normal to for an adult elf just spew an entire brood into a jar and grind them up to be a sparkly, wonderful condiment, bigger ones are a super-rare treat if you can ever find them
anyway this is why you never see elf kids, it’s not because they only reproduce once a century, it’s just that they only actually survive long enough to qualify as “an elf” about that frequently