I work in a super young, very small office. Most folks, this is their first job after college. At 31, I'm the third oldest person in the office. The oldest is 34, the second oldest only beats me because his birthday is in July and mine is in October. I'm older than the Boss. I'm older than my direct supervisor, who is not based in our office. While my age is certainly no secret, I don't really look my age, I look a bit younger. And I blend in pretty well with my co-workers, so my age isn't really commented on all that often. Still, it's a known fact that I'm older than them. Which usually works to my advantage, because it gives me some authority and gravitas when I need them to listen to me.
Anyway, three of my co-workers just popped into my office because they had a bet on how old I am. Their guesses were 27, 28, and 29, because, "She can't be in her thirties yet".
Oh yeah, baby! Drinks are on me!