Same here. 90s were me working my butt off to get a Ph.D. which I didn't end up using, and watching my pals who worked at X, Y, Z cashing out. Some very good times were had for sure, but I don't feel nolstalgic about times when I was eating ramen, working 36 hour shifts at the synchrotron and driving a $200 car.

I do feel a bit nostalgic about the 80s; the music, the big hair, and feelings of immanent nuclear doom, and the eventual fall of the Iron Curtain: a very unique feel to this era. Granted I was a teenager for most of it, so maybe that's why.

As for age: the main thing I've noticed is my hairline and my joints aren't what they used to be. Exercise, eating right and occasional fasting seems to stave off msot of the physiological effects of aging. I'm pretty sure working in a creative field (and being around a lot of younger people) helps a lot with the psychological aspects.