Personally, I went really nerdy and converted 21st of November into the 15 days of Autumn. Me being me though, I also forgot that 15 is half of 30 so spent 5 minutes messing around with percentages. On the other hand, I suppose you could say that Robin's birthday suits her perfectly because just like trees in autumn, not all of her is there so to speak XD

Would like to clarify I'm not an accidental valentine baby before someone makes that joke lol.