Music can be difficult, especially since there is only a fraction of the exam which you can study theoretically for.
The actual exam is split into a practical exam and a theory exam. For the practical exam, you will be required to perform 4 pieces on an instrument/singing etc and while it's a good opportunity to get marks, it can be very stressful and nerve-wracking. It will require lots of practice which I found can eat into study time, but it can be worth it if you are happy with your performance.
Another aspect of this can consist of a "clapping back" exercise or sight-reading on an instrument of your choice.
The actual exam in June can be difficult as it is unpredictable, with a lot of listening skill required. You can study for certain elements, such as musical features of set & choice songs and set & choice works (examples include knowing the instruments, key, tonality etc). There is also some composition, triads and the dreaded Dictation which the majority, but not all, of students - including me - find extremely challenging.
Music isn't the easiest subject out there, but if you put in a lot of work for the exam - practice consistently for the practical, listen to your set and choice pieces and use past papers - it's manageable.