Future education help?

I am now an high school student from Indonesia. I have take 5 subjects of IGCSE. There are Math, Physics, ESL, Biology and Chemistry. In Math and Physics I got an average score, C. I am still waiting for ESL, Biology and Chemistry mark. But, my homeroom teacher told me to set up my future now. After IGCSE, now, I going to take A-Level in Biology. I still confuse on my future education problem. What my problem is? I like to study Humanities and Social Science though, and my score isn't bad at Social subject (even though I attend science stream cl, but unfortunately my school doesn't have any IGCSE on Social Science -_-). Some teacher consider me good at Social Science (History and Civics), rather than other my friends. Last week, I have seen a brochure of NUS. I surprised when I found that NUS has double degree on Law and Life Science. Oh yeah, I forget to tell you that I wannabe a diplomat, even I am an introvert (some people recognize that introvert person isn't suitable for jobs such as being a diplomat, is it true?).. Now, help me! My time in highschool is still 1.5 years again....but I am really busy in this 1.5 year! I must attend A-Level papers, National Exams (if possible)... Can you give me any suggestion for my future? Please, I do hope you answer your question..