What is the oldest that it is appropriate for a woman to wear a leather mini skirt?

I am not that old.
Plus I like women, especially ones that would look good in a leather mini skirt.
But isn’t there a moment when it becomes inappropriate?
I see some [older] females in leather mini skirts and in spite of myself I think maybe it’s time to grow up.
I mean, when I was in my teens and twenties, I would wear a sleeveless T-shirt (sun’s out, guns out)
But as I approach middle age it seems silly, guns or not (plus I think I should cover up my tattoos that make references to death).
So what is that age?
Plus, when should guys abandon shirts without sleeves?