Odds are, you were an authorize user on a family members card. Unlike most CC companies, American Express backdates every card you get. Lets say you were new to american express and got one card this year (2010). You apply for one next year, the "member since date" would be 2010 as well. 1995, was the first time you were put into the american express system, even though you were not the primary card holder.
In return, you increase your average age of accounts, along with length of credit history. It gives a nice boost in score. Check your credit reports if you want to see the actual account you were an authorize user for. Also check to see if their payment history was clean. I believe it can effect your score as well. Don't quote me on that tho 
I'm not an AU on any American Express accounts on all of the credit bureau's. I wonder if this has anything to do with the fact that my dad has the same name and address, although we have different social security numbers obviously. He's has some Amex cards. Oh well, I guess I can't complain if it's going to help my score and AAoA 
Just be aware that his info is probably going to wind up on your credit reports, and vice versa.
The CRA's are pretty careless about posting info when the names are the same. 