At the time when the Air Nomads were wiped out, Sozin was 82 (20 years before his death at 102 years old), so Azulon would be around Tenizens age, and Ozai/Iroh would be a child/teen. After the first 20 years of the war spent searching for the Avatar, 80 years would pass, so wouldnt Ozai/Iroh be in their 80s/90s?