Juicey, I was your age when I first stumbled upon this thread, and then I read it in its entirety from the beginning over the course of a week. I suggest you do the same and then come back if you have any questions.
Don't worry too much about the life experience thing. I asked a FLTLT about it who was running an Officer Selection Board information session and his response was that it basically referred to the breadth of experience that you had to draw from in answering questions put to you. I.e. one of the potential things he brought up was that I didn't have a lot of experience leading in an adult environment, and if I couldn't convince the Board that I could on the day and didn't have any examples to back myself up in the interview that I could, the Board may not have recommended me based on my lack of that kind of life experience (they did recommend me, however, so there you go).
I have no doubt that it varies, but ultimately I don't think you should worry. Read through the thread and work out for yourself what you need to do and get on it. And don't mind the dumb posts that I've made in the past. I was *learning*.
