What makes people look behind the times is being behind the curve in their attitude.
In terms of hair, there's been a cross-ethnic reclaiming of one's textured natural hair for at least 10 years and the Youth of Today DGAF that people think their hair is too "extra." A lot of us oldies have gotten on that bandwagon.
At the same time the movement *for women* to embrace one's grey has gained traction. [Because of course men get to be silver foxes, distinguished, etc.]
So even if we want to use "older" as a slur, grey + curly isn't automatically, universally seen as an "older" look than grey + straight. As any number of YLFers demonstrate....
Ditto for grey over dyed-to-cover-grey.
In terms of style, a person's total package tends to communicate a visual timelessness. But in the end, I think it's personality and outlook above all else that communicate vitality.