Is civil service.
A few are identified for fast track, while the rest have to put in time and show with results.
For Ah Ling, she not bad liao quite steady.
2015 - first GE; CEO of Business China
2018 - joined gahmen as SPS
2020 - second GE; promoted to MOS
2025 - third GE; promoted to SMS
After next GE she will likely become full minister, at about 50-51 yo and quite a progressive career.
For comparison, Grace Fu was made second minister at 48 yo and full minister at 51 yo.
It's a long game and one has to be patient esp if you come from NUS like SXL and GF and not smlj Cornell like Jeffrey Siowliao.