Better to make it to the University (either JC route or Poly
route) and major in a subject which is a relevant teaching subject
(ie. closely related to a secondary school or JC subject), then
sign up with MOE and take a one-year Diploma course at NIE.
Your pay will be better this way, and your bond time will be much
less.
If you sign up with MOE with only an 'A' level cert or poly
diploma, you will have to attend either a 4 year NIE course
(paywise almost as much as if you went University on your own), or
a 1 year NIE course (paywise much less).
At the end of the 4 year NIE course, you can teach only primary
school for a couple years, then can teach Sec school. If the 1 year
NIE course (ie. after your JC or poly), you will only be allowed to
teach primary school your whole life.
So my recommendation is - make it to a University on your own first
(JC route easier, Poly route also possible), then sign up with
MOE.
I'm a teacher in a neighbourhood secondary school.