See Chloe, I understand what you are saying.
However, as mature as you come off sometimes ( I wouldn't think you were 12 ) the fact is you are only 12.
You won't even remember a whole lot from this age when you're older, and you're really much too young to be able to reflect on such things already. It really concerns me that a 12 year old tried to commit suicide. I have an 11 year old brother (my parents little midlife crisis) and he experiences a lot of bullying, and our parents are separated and he doesn't have a good home life ... But suicide would never cross his mind. He'd just go hang with friends or play hockey or something. Because that's what kids do.
You have your whole life ahead of you, you have so much to learn, and trust me when I say you haven't hit hard yet. It will get worse before it gets better ... You have to transition into adulthood soonish and then you have a whole new, and mucher more complex, set of problems to deal with.
12 year olds should be able to live and have fun, not attempt suicide and cut themselves.