The route you mention basically falls on private
institution.
You ask yourself, if you are a boss/employer, would you employ
someone from NUS/NTU/SMU or some private university which you never
heard before?
If you want to sign on with any uniform group be it scdf, spf,
navy, army, using a private degree/diploma and sign on they would
only take your GCE O/N level as the highest qualification.
If you want a higher rank, you must sign on with local
univeristy degree or diploma.
Having say that, have you ever think if its to easy to bypass
the traditional route and get a degree before 18, why do ppl still
go poly and eventually local uni for degree? 