No. But when you are 71... 
I have watched people quite carefully, I suppose I have always been an observer, and I think that, in the main, it's over 70s that seem to suddenly go downhill. It seemed to hit my mother at 74. She seemed to shrink all of a sudden. However my stepfather is 78 and looks fit as a fiddle and much younger, most unfair. It varies hugely, but 70 does seem to be the average, I feel. I do know a fair few people in their mid 60s who have aged horribly, usually due to living with pain or stress.
As for the smokers - well. One of my younger sisters smokes and she looks dreadful and acts far older, even with my arthritis I can get around faster than she can and I have nowhere near as many wrinkles.