Yep! It's all in the attitude. I went to a Highschool reunion when I was in my early twenties (5 years after graduating) and some people there already looked ancient. After only 5 years! Meanwhile, I run into some people now, almost 20 years later...and they look the same as they did back then (give or take a few wrinkles lol but they don't "act" old) If you decide you are old, then you will be old.
I really admire my grandfather, because even though he says he feels old sometimes and that his leg really bothers him, he still goes for his daily walks and pushes through the discomfort...because he says, staying home and not doing anything will just mean he has given up and that his leg would only get worse, not better, and then he'd be stuck at home all the time. I think about him when I'm working out and feeling like I can't do it. If he can push through his obstacles at 84, I surely can at 34!