You were born the year before I graduated high school. If I were you, I wouldn't feel too old.
I'm 41 and I still feel pretty much like I did when I was 25. If anything, I feel better than I did then, because now I'm married to the right man, doing the right job, and living in my own house instead of a crappy little half-double shotgun apartment. AND I no longer smoke, so I save more money.
Being 25 was great. Being 41 is also great, I am happy to report.