What is old age? I don't think anyone can confidently give an answer. I still remember vividly a conversation, circa 1990s, I had with Father Kung, my old pastor of Pei-tou Catholic Church in the 1950's. Father Kung was alluding something about being old, he was in his eighties then. I told him that he was not old at all. Then he asked me what should be called in his age group if not old. We discussed and came to an agreement that he was in the ripen mature age instead of old age! I think I am entering to the ripen mature age bracket now.
Of course I had observed first hand my parents went through this stage of their life. They took it for a stride and generally taken it for granted that's just part of life. They were both much healthier than I am now as I remembered. That may be just my opinion. Last Christmas season when Tina and her whole family came to visit us, she once commented to me that I am in "ridiculously" good health! I was happy to hear that, of course.
Now old age is not something tangible, may be just a frame of mind. Like they say "If you don't mind, it doesn't matter!" In reality, however, it's something one just have to face it, accept it, and live with it!
Oh, well, Que sera sera, whatever will be will be!