melmel I believe Singapore is a very competitive country in the ODs right? How many people showed up?
I read about cases like your OD, and then cases where they accepted to assess people aged 20 because they turned 21 in just a few months (usually no more than one or two months away). And then I barely remember to have read one case that someone flew to Dubai aged 20 but turned 21 before finishing training....
Nevertheless this last cases must be myths or really awesome people that EK couldn't miss having! But oh well, funnyrose if you turn 21 in January then take this time to gain experience and to be really prepared for an OD or AD closer to your birthday. Good luck!