can immortals be said to have a life-cycle?

On reading The Silmarillion I was mildly bothered that, in a story mainly about Elves, Elvish children are never mentioned. (Half-Elf children appear in a couple of episodes, as baggage.) Children are relatively scarce among immortals (because they spend a smaller fraction of their time as children), but still, a number of prominent Elves were born during the period chronicled, and you’d think at least one of them might have done something memorable before coming of age.

This cartoon suggests an answer.

2006: That site’s archive has been reorganized and I can’t find the scene in question. It had several humans and a vampire chatting over coffee. Human: “You look about nineteen, but being a vampire you could be any age, right? So, are you centuries old?” Vampire: “I’m twelve.”