Hi S2K4,
I majored in acturial science in uni, so perhaps I can answer some of your questions.
First of all, acturial science is essentially put, risk calculation. A degree by itself isn't exactly very useful because it is like accounting, you need professional papers like ACCA etc. For me, I took the SOA
www.soa.org papers. Only 1000+ people in the world have taken all 8 papers to date. There is no passing mark for the papers. Only a certain percentage will pass, which means scoring a mark of 99 for any paper wouldn't guarantee you a pass.
Second, you really have to be interested in statistics and math if you want to take acturial science. Unfortunately, I can't help you with the entry requirements cause I did mine overseas, but just as a rough guage, my school required 4As, 2s + essay + SAT + interview. If you need more info, just let me know.
Regards
ps: just checked with my friend. If you go into NTU NBS, you will only get to choose to major in act sci only in 2nd year, provided your grades are good enough.