Hi. I do not think you can get to NUS or NTU science with your
scores. You need to check the websites of NUS and NTU again.
Ultimaonline's website has the link. Google for Bedokfunland JC for
his website.
You may choose to retake your A levels, or go PSB or SIM
(Singapore), or go poly (long 2 or 3 years), or go overseas uni
maybe in Australia (more economical maybe than UK or US; need to do
currency calculations). A levels is graded on a bell curve and you
need to contend with bright students from the top 5 JCs and the
bright students of other JCs too. There are private schools for you
to retake your A levels, if you prefer a more structured
environment.
All the best.
Can someone else comment? Those who have been through the recent
A levels are in a better position than me to comment.