Interesting TWNPPL. A Singaporean used not to be able to join the airline until he was twenty six! Had to have completed National Service first, then he would have had to amass the hours and sectors necessary for a first command, usually on the smaller fleet, the A310 in my day. A non-Singaporean joining younger than 26 would have had a time penalty attached to their TCOS to ensure they didn't get an advantage over a Local.
The youngest ex-pat B744 captain I knew in SIA was in his late thirties, about the same age that a Singaporean would hope to make it.