Everything that has to do with the physical functionality of the organism – i.e. your body – will decline with age. You can work hard and do your best to maximize its function as you grow older, but let’s be clear, it will decline no matter what. So there’s that.
The brain, however, is different. Our brains don’t really work on speed – compared to hardware, they are pathetically slow (obviously some are slower than others). Where they shine, indeed, what separates us from traditional hardware networks today, is that human computation is massively parallel.
What does this have to do with aging? Just this: if you have maintained your cognitive capacity, and you had a decent amount to start with, any minor slowdown in information retrieval is more than offset by a lifetime of pattern recognition and sophisticated cognitive mapping.
Your understanding of the world around you and how it works just continues to become richer and more nuanced. Your ability to recognize patterns in human behavior and the environment helps guide your decisions of how best to spend your remaining time, while also allowing you to see weaknesses in your previous thought patterns more easily.
Somehow, paradoxically, life actually gets better.