1. Whether it is a good decision or bad, no one can comment. Its an individual decision and will only produce result after your studies.
2. Acceptance is based on credentials of individual which must meet the entry requirements. If requirements are met, I belief there is nothing to hold you back.
3. I think you should prepare financially as Singapore education cost and living standard is not cheap compare to Vietnam. English language is definitely a must as it is the main language of all the courses being conducted. Lastly, you should find out about Singapore and your course requirements before heading here.
Hope this helps...