The ticket was booked in A class. I was originally booked in First on the flight to EWR (2 class aircraft), but due to a delayed departure, I opted for the JFK flight. The admirals club told me that there were a number of seats available in First, and one available in business. She said it would be up to the gate agent since A class on AA is business. I got to the gate and told the agent I had just flown around the world in First, but she would not even listen and told me that in a 3 class aircraft, A is business. This seems completely out of line for a ow RTW fist ticket. How cann AA be different than the rest....By the way, First was half full.