I know I'm getting on, and I realise AB can (and does!) put years on you, but why am I a year older in my profile when I haven't had my birthday this year yet?!
I've heard there are countries where your birthday is automatically January 1st, but I want to wait till March!
In China the moment you're born you're aged 1, then after new year (their new year) your 2.
That's why in the press one of Gary Glitter's victims (although Vietnamese they use the same system) age varied from 9 to 11.
Often in China you'll ask someone their birthday and they don't know, although that's mainly in rural areas.