Myrna- I was in the exact same situation as you- booked an AA ticket on
Etihad almost 11 months ago for my nephew but only booked the chauffeur last month after the policy change. Received confirmation almost immediately and ticket stated that the chauffeur was booked. My nephew flew out last Saturday and I was extremely nervous that there would not be a car waiting for him. However he messaged me last night and told me that the chauffeur was there waiting for him and there were no dramas. I had incorrectly told him that he should receive a text from the driver and so he was a bit worried when a message wasn't received. ( when beening picked up at the airport I have never been contacted by the driver only with home pick up going to the airport). So I think you will be fine.
At the same time of booking my nephew's chauffeur, I attempted to book a chauffeur for myself as I also had a ticket booked under the new policy. Even though the website said I was eligible I received the same message as DC3 - unconfirmed not eligible.