Hi Keith,
First of all, I'm glad you haven't dropped out of school yet to
pursue anything.
That shows at least you are mature enough to be considering it as a
serious option but not jumping into anything yet.
In most parts of Asia (if you're not planning of staying in
Singapore in the long term or have plans to leave) education is the
most important thing in a young person's life.
Sadly, despite the fact that university doesn't make a smart
person or doesn't necessary mean you're talented/"educated",
emphasis is still placed on the 'paper' qualification as opposed to
the actual wisdom attained from it.
This is not to say education isn't important. The rite of going
through schooling, university and even further education is very
significant - the people you meet, the things you learn, the
networking - is all a wonderful life experience that teaches you to
socialise, problem-solve and adapt in a social environment.
Another important thing to remember is that you are still young
so your plans might change in the future.
If you quit school now to pursue the certificate you think you
want, if things change in the future (maybe you decide you want to
be a chef? Or you fall in love with financial planning?) - you'll
be stuck with a relatively obsolete specialised certificate, many
years of experience but no formal qualification to really help give
you a push to the other side.
Formal qualification is important and either way if you want to
get that technical cert you can always get a degree qualification
in that field so you will be able to achieve proper career
progression.
I advise you to finish your 'O's, go to poly/take your 'A's, get
into Uni or go through distance learning to attain your degree
qualification.
That way you at least know that if in the future circumstances
change you can always rely on your degree to jump ship to another
field, or diversify.