I just finished my IB Diploma this year. I did:
-HL Maths
-HL Physics
-HL Geography
-SL Chinese A
-SL English LangLit
-SL Environmental systems and societies
HL Maths and Physics can be rather difficult at times, so be prepared to spend more time on HL Physics if you're really going to do it. However, you do not need Maths and Physics to this level to become a pilot. SL Maths and Physics would be more than enough. In fact, if you did well for IGCSE Maths and Science, you need not worry at all. Good luck!