I'm mid 60's, with very short hair. I'm with OneAndDone on this one – you reach a point where certain fashions in hair, clothing, and makeup start to look harsh, or unrealistically silly. And even more importantly, for me, is that I just don't care as much to try to maintain youthful beauty (an impossible dream at best).
I do henna my hair once a month, because the color has become very patchy – ranging in areas from original bright red to pinky-beige to stark white. Very odd. But I've settled on a darker, quieter auburn, because the carrot-orange of my youth is simply shocking now.
As my energies decline, so does my sense of available time, and I use what I have for more important pursuits – enriching relationships and learning about who/what I truly am. (That's what the people in my life care about, too.) Still working on it, but I know I'm not my body. Appearances are superficial – once I get past "neat, clean and self-respecting," it's all pretty much superfluous. I refuse to fight a losing battle with the mirror, or with fashion magazines.
Short hair is easier, cooler during menopause, and simply more fun for me. I hope you reach a place where you're comfortable letting go of your youthful looks – aging brings beauties of its own!
ETA: I do have a few older friends who still look good in long hair. They are very slim and have very little facial sagging, and it still looks great on them. It doesn't work that well for most women, though.