I got my first grey hair when I was 9! I had sparse greys in my teens and 20s and didn't bother coloring. I just plucked the ones that stood up above all the rest. I started coloring about 10 years ago when I was about 10-15% grey.
Now that I'm more than 50% on top and about 25% underneath, I've tried embracing on and off for the past year, but I'm over that now. With my hair colored, I look refreshed and rested and 10 years younger than I am. With the grey at my temples and around my face, I look tired and haggard and at least 10 years older than I am. It's not about whether I look older or younger for me, but I'm tired of people asking if I feel okay or if I'm tired. I have started using one shade lighter than my natural hair color, so the greys are more like highlights instead dark brown.
I agree with TriciaRose that not all shades of grey compliment all skin tones. I've tried all shades/tones of blonde wigs and never found one that flattered my skin tone. Similarly, the grey at my temples and around my face is NOT
a flattering shade. I could probably try to correct this with makeup, but I have NEVER worn makeup, and I don't plan to start at my age. Now, if my greys were silver like my husband's (or Bararosa's below), I think grey would look better on me and I would embrace going grey.
As for glasses, I like the way I look in my clear rimmed and wire rimmed readers better than how I look in my dark rimmed ones.