......"using a calendar converter I discovered that because the Hebrew calendar has 13 months and is slightly longer than the civil calendar a Hebrew age is not always the same as a civil age".
The Hebrew calendar has only 12 months. In order to keep it accurately it adds a 13 month 4 times every 19 years. In principle the difference in a particular age is not more than a few weeks and it's automatically amended every 19 years, when the Gregorian and Jewish Calendars meet. Dr Shimon Barak
