It's a fun subject when you start off but gets extremely stressful. I'm doing it right now and I find so much of my time is spent doing my graphics work that I'm not getting time to revise other subjects. I thought it'd be a creative outlet but a lot of it is writing and research and it's not even fully about how artistic you are, but about how your portfolio looks and how you evaluate your product etc. Everyone in my graphics class (that's 30 people) regrets choosing it for GCSE. If you really want to do it, go for it, but remember it will take so, so much time and patience and effort so only do it if you'll be fully dedicated.