I've let my fine, thin hair go white, and actually with a decent cut it looks reasonably OK. I started going grey in my late 20s, I did dye it for a while, it looked horrible, when you go grey your skin colour changes too, so you have to be careful it rarely looks natural.
A few years ago I went to a concert with a few 1960s bands, watching them from my theatre seat I was thinking they were wearing well. Then we had the opportunity to go and meet them and get autographs, my bubble was burst, these aging pop stars had all got dyed hair. You just can't fight the aging process.