When I was younger (back in the late 50's) I used to have vivid pink highlights in the front of my dark brown hair. Did them myself at home, but did need firstly to bleach those hairs before applying the pink colouring.
I stopped these highlights as time went on, too much faffing around as my hair did and still does grow extremely quickly, but always kept it coloured. As I got older I used a lighter colouring, and was turned 70 when I finally decided to stop using that and see how grey I actually was. About 70% was the answer, and I love it, just wish the rest would go the same colour - I so envy people with beautiful full heads of grey hair, cannot get that out of any bottle.
Personally, I believe that whatever we do, if we feel good about it then is quite correct, had my long hair cut short after the birth of my third child some 45 years ago.