Well I dont know if this counts but when I was 3 I made a rubberband guitar out of different colored rubber bands on a shoe box, I then put stickers on the top of the shoe box, like notes, and that was my first "composition". On the piano I started composing fragments when I was 6 and I really started getting serious and creating full songs when I was 9 and 10. At 11 I wrote my first full band composition (even though it sucked and I scraped it later) I've written about 4 good compositions on finale so far, but I am working on 2. I have about 7 really good finished piano pieces one being a duet. I am 13 right now.
