I am also 31 (gasp! well, almost -- I've taken to rounding up!) AND, say that no one wears hose anymore.
I grew up in Southern CA, and while people were maybe wearing pantyhose when I was a kid, and I would wear them sometimes when my mom made me (for Mock Trial, etc) I don't think people really wear it anymore. And now I live in Northern CA, and notice the same thing.
Here's my Pantyhose Fashion Theory: I think that wearing "nude" pantyhose, to "fool" people into thinking that your legs are bare but uniformly orange, is sort of like being denial -- if you want to look bare-legged, just *be* bare-legged, people -- it's OK! Pretending they're invisible is like the Emperor's New Clothes, but backwards.
I think it's pretty acceptable, at least in California, to be sporting a business look that's sans hose. (I think I don't notice, except when someone *is* wearing hose, and then I think, sheesh, what does she think this is, the 80s? No one needs you to wear hose, chickie! Liberate yourself!)
But, wearing hose/tights *consciously,* in a color that's on purpose (as opposed to "Not-Really-Invisible Nude," to complete your outfit, to de-bare-skin-ify yourself, and/or to keep you warm, that's perfectly acceptable. I'm a big fan of colored tights, and they totally do keep you warm in the winter.
And don't wear pantyhose with open-toed shoes. Or sandals.
Again, that's the "I'm pretending they're invisible!" desperation.
I haven't worn pantyhose (tights yes, but not hose) since . . . 8th grade? (Maybe high school, when my mom made me.) And I've never looked back. Woohoo!
And that's my completely non-authoritative Pantyhose Theory.
And my bottom line: YOU, dear reader, wear whatever you want, and rock it!