Unlike many other professions that follow a linear path to entry, beginning a career within the music industry can happen in a variety of ways. Some major music executives entered the field directly from high school, while others have advanced degrees in business and/or law. There is no hard and fast rule, so what I'm going to discuss here is a variety of different options that are available to you. Which path you choose will depend largely on what you're exposed to, what your interests are, and the level of motivation you have.
Of all the things in that list, motivation may be the single greatest factor that will determine if you end up in the music industry (or any industry for that matter). The path of least resistance is often the wrong path in this business. If you think you really want to be in the business, begin your journey now. The earlier in life you begin - generally while in high school or college -- the better off you'll be. So, without further ado, let's get on with it.
I'll begin our journey with an overview of the path that I took to get into the biz, and then give a more generic description of things you should think about doing as you begin your own journey into the music industry.