Don't feel bad, I would have thought as well. I guess the Huck has been rode hard and put up wet a few too many times.
However it's not that unusual. My brother is 6 years my junior, and at our father's funeral he was at great pains to explain that HE was the younger brother. (and that his son was indeed HIS son, not mine, since my nephew looks quite a bit like me.) My wife is oldest of five, yet both her sisters, 2+ and 7 years younger both look older due to that same "rode hard and put up wet" phenomenon.