Music is great if you're good at it, however, making you less stressed - it won't.
The coursework entails two performances, one solo and one accompanied and two compositions, a free and one from a brief.
Your teacher will set bizarre and irritating deadlines for these, which make up 60% of your music GCSE.
You find out very quickly if you're good at music when you're thrown in front of a computer and asked to compose a piece from scratch that is worthy of a level 7+.
Another problem I am finding with music at the moment (39 days from exams) is how there are no resources online to help you. None at all. And the specification is useless.
Have fun.