Home GCSE's ?? What do I do?

Today I found out if I got all of my options for GCSE's, and it turns out that I didn't get music as one of my subjects next year. I have been wanting to do music at my school since I started, but it isn't possible to change it, as it won't fit into my timetable. It doesn't relate to the job I want to do in anyway, but I really want to do it. My mum has said that if the school supports me, I could do it off my own back, in my own time, but I'm not sure if I will be able to handle it. Without it, I would still have 10 GCSEs and an addition maths (college level) qualification. I'm willing to work hard on it. I'm not sure what to do. Do you think that it will be worth the extra effort, and do you think that it will be too difficult? Any advice will be greatly appreciated :L