I'm a little older than you and have also experienced this so you're not alone hah. Especially when I go back and look at pictures of my parents or grandparents at my age....they all looked old and weathered. Other than some grays in my beard, I think I've held up fairly well all things considered.I think people my age l look so much older than me. I’m not saying I look young, just that if I see a 42yr old they seem older to me. I think I’m in denial that I appear older than I’d like to admit.
Like you said, maybe it's just me - but I don't think I look (or act) my age. Just yesterday I stopped for lunch near one of the state universities where there's a ton of students around, and some 18 or 19 year old girl was at the counter. She asked me if I was a grad student lol. In my head I was like "I started college before you were born for fucks sake" lol. I guess I'll take the compliment though