I'm departing Melbourne in October on TG 462 at 00:30; 30 minutes after my birthday, so don't have to worry about such things.
However, Bangkok (the destination) is 3 hours earlier, so in Thailand it would still be my birthday (but not when we land at around 05:30).
Maybe I should just drink in the lounge, fall asleep on the flight and not be concerned :-)
Cheers,
-Cyborg