Well, I think you should start with melody and rhythm. When you get that you should go into your feelings and emotions, look for what you want to express and write it down in simple words, sentences or anything. After that you structurize it into that previous melody that you constructed. If you have an instrumental first it's also good to get inspired by it. Generally speaking - it's much easier if you have the music first and then go with lyrics. I'm writing things for 5 years by now and after training my skills I'm finally up to showing up soon. I keep my fingers crossed for you as well. Do what you want to do and don't you dare even thinking about the consequences. Okay, you may worry if you think that some of your actions might make you starve. Or actually.. even if you'll be starving - don't worry. Passion and dedication can make you go through all of the worst things with your chin up and win.