Mea Culpa. There are three Johns that have been given credit as the author of Revelation, written about 95 AD. No one is REALLY sure who wrote it, but if it was John the Apostle, and 95 AD is accurate, John is one long lived person. Assuming dating in the era is correct, he would be in his '90s when it was written.

The reason the authorship is debated is that the earliest copy known to exist is in Greek, and John the Apostle wrote in Aramaic.