When are you going to start being you? I bet you haven't even begun to figure that one out! You haven't got up off your ass and clarified who it is you want to be! Why Not? Get up and don't make excuses!
You mustn't wait to do. Choose now to get started. If not now! When? Do you want to achieve something? When your life is on its last breath—and it will be—what would you have wanted to achieve? Does it even matter? Go ahead and write that shit down! Put as much detail as possible. If you want to have written a book then create the deadline to do it. Set your goal now and define how you're going to achieve it. As Jeff Goins says, write 500 words a day. Determine how many words you need to complete your book.
So, set your deadline. Determine the number of words you need and write until you've reached your goal. A fully written book! You could set a 12-month deadline and a 35,000-word count. Take 35,000 and divide it by 12 months. That's right around 105 words a day. You can do that now. If not now! When?