How do you know when you're old?

I'm 54 years old, and I'm wondering when I have to admit (and surrender) to being Old. Some people I know are frail and sickly long before they get to their fifties. And yet other people are in their 80's and 90's and still seem pretty healthy and perky. So my questions is: how old will I be when I feel old? This morning some children in the neighborhood were trying to be polite, but they pretty much told me they thought I was old. So I told them that when they are about 30 or 40 years 'old', THEN I will be old. They've probably never thought past next week, which is why their little faces looked at me so strangely. Whatever. They WILL get old! And I guess I will, too. I hope I get to stay healthy and bizzy until 3 days before I die. Three is my favorite number....besides, 3 days should give the kids time enough to get here for their last hugs. I already have a list of the things they want when I die, so I don't even have to worry about that! I hate math, but as I figure it, I have about 40 more years to live and love. There are so many things I want to do in those years. :) To start with, I'd like to go to New York and meet my penpal from 4th grade. I'd like to visit a foreign country. I'd like to get my books printed and shared. I'd like to make my living room and front porch more wheelchair friendly for Rebecca. But I DON'T want to study to become a nurse. no no no no no!