Hello m’lovely, honest answer.. no, you probably wont know what you want to do, you will probably finish school, go to college/ uni/ wherever still unsure of what you want to be. You may decide what you want to do as you grow up, but this idea will keep changing, right now you may want to be a writer, next year a teacher and the year after a police woman. It will feel as though you are driving in circles but you will get somewhere, you will find a career that you enjoy and is right for you. You may think that you have it all figured out when you leave school, but you will probably not be what you think that you will, because very few end up being what they wanted when they were younger. There are so many careers out there that you have no idea about, I mean look around,;there is a job for everything. You feel as though your only skill is writing, but there are so many things that you havent tried yet, so many hidden skills that you will gradually find that you have. In essence I am trying to tell you not to worry, you have time, you will get somewhere someday.
Have a wonderful day