Blazer,
I am not trying to discourage you from going to MASI but you should seriously consider your options if you are not selected by SIA. I have heard of quite a few MASI graduates failing the second interview.
What happens then? If you are Singaporean, what good will a CPL/IR or aviation degree do you? Unless of course you are willing to accept a career in the non-flying side of things..e.g. CAAS...ATC
90 percent of all cadets..including myself have absolutedly no flying experience and we still got in. You really don't need prior experience or be in a related field.