Time travel shouldn't affect a villager's birthday party.I've celebrated a villager's birthday,TTd ahead a bout a week and TTd back to the day of their birthday and I was able to go to their birthday party again.If your town is set to the current date then it's Pecan's birthday today(Sept.10) unless you're across the international date line where it's the 11th and it would be Pee Wee's birthday.