I'm starting to get the first whites in my beard and hair but I feel much more energetic and clear-minded than in my 20s. Like you, my nutrition and habits have all improved since then.
I think worrying about aging is a bit of a waste of mental space, I deal with it as I deal with intrusive thoughts. I'd rather focus on what I can do to live a better day and be more present :)
I think as we get older we also reach a point where we don't really care that much about how we look any more and realise we're better off just living our best life today.
I feel sad for those who feel like they have to fight visible aging for the sake of their careers.