That even though you feel you have it in you to be a published novelist when you're in your early teens, it's all the hard work of creative-writing courses, daily writing and revisions, submissions ( and decades of rejections) that will finally stand you in good stead to become a novelist well past middle age. But never, never give up and keep plugging away until it happens. It WILL happen!
Set achievable goals each day in your writing and promotional work. Otherwise it becomes far too distracting and depressing because it's overwhelming. Be sure to have set times at the end of the day when you are NOT thinking about your work, but doing something fun and relaxing.