You received A1 for English in the GCE'O' levels.
That should indicate that you are indeed proficient in the
English Language.
You should check if the Korean authorities recognise the
certification.
oh!
BTW I do not think Singapore have the status of Native English
Speaking country. Singapore is not like Australia or New Zealand.
What with Malay as a national language, English as a working
language, and Mandarin as the preparatory language for the future
rise of China, it is a mess here.
Yes. I checked earlier today. Singapore is indeed not considered
a 'Native English Country', or at least by the South Korean
Ministry of Education.
The ten countries they consider nationals to be 'Native English
Speakers' are the United Kingdom, the United States of America,
Canada, Australia, New Zealand, Nigeria, Jamaica, Ghana, South
Africa and Ireland. How the heck Nigeria, Ghana and Jamaica got in
that list I have no idea.