I don't think age has anything to do with it....maybe your ability to adapr easily to new things may be slower. I ride with 3 other ladies from by bike club. All of us ride road bikes and are over 60! Although I do prefer my road bike to my hybrid for long rides, I understand that some do not like the feel of a road bike. However, I would agree that you might want to wait and try again next season before selling the Felt. I really got into my roadie after putting it on the trainer for the winter. I would alternate the hybrid and the road bike and found the roadie much more comfortable for longer sessions. It is even better outside!!!
Good luck with your journey and what ever decision you make will be the best for you. Just make sure you keep on riding and enjoy it.
P2
2018 Trek Silque SLR6 - Selle SMP Glider
2018 Specialized Dolce EVO Comp - Selle SMP Glider
2011 Trek Madone 5.2 WSD -Selle SMP Glider
2013 Giant TCX W - Oura 143