Our attitudes toward aging change in that “old” depends on where you are. When I was 16, and my sister Nancy was 29, I suddenly realized, to my horror, that one of us was about to be 30. I went around saying to everyone, “Poor Nancy, she's almost 40,” because to me at that time, 30 and 40 were about the same. Later, when Nancy was 40, she said she didn't mind because, according to me, she had been 40 for a decade.