Reminder: Luke and Leia being born on the same day and them finding this out isn’t and wouldn’t be some amazing OH WHAT A STRANGE COINCIDENCE AM I RIGHT??? HOW WEIRD!
It’ll only seem obvious in hindsight. (And even then, it’s a minor clue, honestly.)
Because I’m pretty sure there’s billions upon billions who share their very same birthday, and the chance of them sharing a birthday with at least ONE more person on any given rebel base/ship is… pretty large, you know?