On elf children

[Raynor]

Originally Posted by A Little Green

It would sound silly to me that they would be adults in some twenty years and then live as adults for thousands of years... But also the thought of two hundred years old children sounds silly.

Indeed; it is somewhere in the middle:

Originally Posted by Laws and customs of the Eldar, Aelfwine's Preamble, Later Quenta Silmarillion, HoME X

Not until the fiftieth year did the Eldar attain the stature and shape in which their lives would afterwards endure, and for some a hundred years would pass before they were full-grown.

They would wed in their fiftieth year and would generally have no more than four children; their time of generation was in their youth or early life, within a short space of years after they were married. I will look some more on other legends, such as the 144 First Elves or the march to Valinor, perhaps I can find something interesting about the rate of their population growth.