It has finally happened to me-wrong age assumption.Here is the conversation:
coworker: I don't feel at all like I am nearing 50. I feel closer to the age of you guys. You're in your mid-thirties, right? That's more how I feel today.
me: (shock). No, I haven't hit thirty yet. This is the big year
coworker: Oh! You are still in your 20's? I thought you were somewhere in your mid-thirties.
me: (feeling really bad now). Nope, I turn 30 this year
That is basically the gist of it
At least let me enjoy my last few months in my 20's people!