I started turning grey in my late 20's. I'll be 55 tomorrow and I've been coloring my hair various darker shades of brown for 25+ years. My cousin, who is six months older than me went 'natural' - - - - aka stopped coloring her hair and let it go gray and, honest to God, she looks at least 10 years older than me.
I'll keep coloring, going kicking & screaming into that 'grey good night' - - - -