Tell me at which moment, you feel old?

In May, the temperature in my city has reached more than 30 degrees. So I bought a sundae and ate it while walking, but the moment I got it, I only felt "so cold"! This has never happened before. You know, when I was a teenager, I could eat ice cream with my best friend on a snowy winter night. But now, I feel so cold that I can't eat. In the end, the sundae was not finished, and more than half of it was left, which is unimaginable for people who like ice cream so much. Then, a sentence popped up in my mind. It turns out that I am old and will not be the same as before.