How old do I look?

Not that I'll post a picture but ...

The last few years I have been getting the strangest reaction from female bartenders. And I guess I should be grateful but when I look at myself in the mirror, its difficult to believe...

I am 31 years old ... I get carded all the time...

Three notable times - 2 in the last year, all at different places:

Bartender #1 cards me, reaction: "OH MY GOD!"
Bartender #2 cards me, reaction: "I need to retire!!"
Bartender #3 cards me, reaction: "WOW!"

So I contemplate this... could I potentially look like I'm carrying around a fake ID? I mean seriously ... I had less of a problem getting into bars between ages 20-23 than I do now.

So I guess I'll just be thankful and chock it up to good genes. My mom doesn't look anywhere near 58 years old (that freaks him out actually) and I would say my grandmother doesn't look anywhere near 84.

Still, its weird to me... I mean, I may not look 31 but I know I don't look 20 either!