BWB
Section : Formation of the White Tower

"given the exceedingly long lifespans of Aes Sedai during the Age of Legends, it would seem possible that at least some Aes Sedai who were alive at the beginning of the Breaking, even some who lived when the Bore was drilled, we're still living when the Breaking ended. Over the centuries there has been considerable speculation, some rather wild, about this. However, the increasingly violent nature of the times, from the drilling of the Bore to the beginning of the War of Shadow, the war itself, and finally the centuries of the Breaking, suggest that no Aes Sedaialive at the end of the Breaking had survived that entire span, or even a significant portion of it."

Regarding the calendar there are numerous mentions that the actual dates got muddled because of conflicting written records... And that a portion of the WT Library burned toward the end of the Trolloc Wars. Also TV was under siege by Hawkwing for 20 years leading up to the second calendar change which was followed by another 100+ years of wars, likely creating many of the same issues (conflicting written records) that occurred during the Trolloc Wars.