Elidibus imma thinks that Avan must have not heard him properly.

So he smiles and patiently explains, "It is difficult to measure my exact age, as I was alive for quite a long while before a marked event took place upon my world. Since that event I have lived for over twelve thousand years, and an untold number previous as mentioned."

What was it Emet-Selch had one said? A thousand, thousand mortal lives? It is an appropriate estimate.