I think it's a mistake to think, 'Am I going to write a young adult book, or do I desperately want to write a book for adults?' I think the better ambition is to try to write someone's favorite book, because those categorizations of adult, young adult, become kind of superfluous.
I procrastinate in spades. In my defence, I also try to have all other distractions solved before I can concentrate on writing. My small theory is that to write for three hours, you need to feel like you have three days. To write for three days, you need to feel like you've got three weeks, and so on.