Happy early birthday!

A few weeks ago, I was invited to a birthday party. It was a Saturday, but I knew the person's birthday was on the Monday two days later, so the person was celebrating two days early! I was highly confused. Was the birthday-date information I had wrong?! Or did they plan the party for Sunday night and put Saturday by coincidence on the invitation? There's an old superstition in Germany, that it's really bad luck to wish somebody a happy birthday before their actual birthday. And on the party we did that of course and sang happy birthday. I didn't talk to anyone about the possible bad luck we have in Germany, but I was confused.

Then I got another invite for an early birthday party. So it just seems to be common around here. Fortunately, I talked to a friend the other day who's going to Germany soon, that he wondered why Germans can't celebrate their birthday early and that it's bad luck.This was very illuminating! Apparently, it's really German to not do congratulate someone early.