I want a book published. How?

I am young and when ever anyone reads ir hears about my book they tell me how great it is how creative, you were meant to write . Though one friend asked if I were going to try to get it published. After she asked that i asked all the people who read it and they all told me to go for it, but I have no idea how.I want to do this without a agent and when I say i'm young I mean I am 12. I know that is a long shot, but i am the most determined person alive and I have to know that I did all that I could to stop trying. So please help.