I am almost 68 and have hair as thick as I had when I was 18 with no gray. Theres nothing like genetics when its working in your favor LOL.
79 here and same story.Downside is accusations of toupee, hair dye etc.
While my [head] hair is the envy of all (har har) my facial hair is 100% gray. I finally shaved off my mustache of 40 years because it made me look even more like I dyed my hair.
When I am accused of dying my hair, I always respond with "Look at my face. Is dying my hair going to get rid of these wrinkles? Be kind of pointless, don't you think?
Both my brothers were gray before 40. The luck of the genetic lottery.