I was initially hesitant to reveal my birthday, as I feared that one of my various online accounts' sole security question was "What is your birthday?" After some thought, I could not think of any, which suggests that even if it were an issue, any such account would probably not be that important.
Since I am only 20, I sort of feel like this day in the shadow of next year (not to mention in the shadow of those who are turning 21). I have had a number of conversations like this:
Friend: Happy Birthday!
Friend: So, are you 20 or 21?
Me [sighing]: 20.
Friend [disappointment apparent, as visions of a wild and crazy birthday party disappear]: Oh. You're young!