It is true that a cigar begins to age at the moment it is rolled. (And, yes, tobacco begins to age the moment it is picked.)
Some brands contain date codes which tell you when they were made. If yours do not, you may wish to ask your supplier when he received them to help better understand the cigar's age.
Aside from a date code, there is no real way to tell. It may be best assume they are not aged at all in order to ensure the proper amount of aging. If you have some cigar smoking experience you may wish to smoke one and tell for yourself.
Frequently popular brands of cigars are rolled and shipped out immediately due to their high demand.
http://www.cigarnexus.com/counsel/aging/index.html
Good luck to you!
-Huminie