Either the waitress that cards you at a restaurant will think you are already married or brother/sister.
Other than that it wouldn't be weird.
I think age would be more awkward. My wife once got carded for a lotto ticket. Which means she must look 17?
Sometimes I dont get carded for alcohol. Which means I look 35?
Does that make me look like a pedo....?
She is actually like 4 hours older than me.
Which brings up having waiters doubt if our id's are real because we have the same birthday...