Philosophy

The more I try to grasp the concept of being 60 years old, the more the whole idea eludes me. What exactly does 60 mean? I don't feel 60. I don't know what it means to feel 60. In my head, I don't feel any older than I did when I was 40. I want to feel this way as long as I live. The only answer I can find is exercise. You see getting older is mandatory. Getting feeble is optional.