Age has little to do with physical ability. Everyone is different. I'm sure that there are some 25 year olds that could not drive a Class A safely.
I congratulate you for you abilities at your age an d wish you many more years to come.
I should add that I am only 72 years old and have no problem driving our Class A with a toad all over the country. I am also able to still carry a 200+ league bowling average with several 300 games in the last few years and I maintain an active pilots license.
I'll know when it is time to slow down. :B