A man taking his daughter to her new friends birthday party one Saturday in spring when he happened to overhear his daughter's friend explaining her party to his daughter. saying:
"I'm the oldest so we usually celebrate on my birthday, but Mom says they don't take reservations here on Friday so we're having the party on Brittney birthday instead"
The man didn't think much of the conversation until it was time to open gifts and he saw two identical girls at the center table start opening gifts together. He hadn't realized his daughter's new friend had a twin. But wait, if they were twins how could one be an older sibling with a birthday on Friday and the other have a birthday on Saturday?
Some clarifying details:
Tiny Hint 1:
The birthday girl is indeed an identical twin and was referring to the Brittney she was referring to was her twin sister
The girls were born hours apart
Their parents were on a vacation when the kids were born