By now the trope mystical white hair is used by everyone and their cat, we have loads of characters who appear young yet have white / silver hair, either because they were born that way / used magic or other powers / had a traumatic experience etc.
Which was the first anime that had a young character with white hair?
Originally, anime and manga tended to have black, dark brown, and redhead hair color. Often it was stylized in the manga pages and illustrations, so many characters might've had white hair then. Although it was'nt really canon design. Then the whole "colorful hair\eyes, sometimes crazy hairstyles" thing became more common as actual canon design in both anime and manga, and thus white hair started appearing alongside blue, green, purple, violet, fuchsia, pink, bright red, grey, teal, cyan, bright yellow, bright orange...
So it might've easily been more than one character at the same time.
