The best time in history to start a business is right now. We're living in (relative) peacetime. Interest rates are incredibly low. Technology makes many things easy that used to require endless preparation and drudgery. And (and here's the critical factor), you're alive. The odds of you existing are incredibly low. He's how Bill Bryson calculates the improbability of your existence, in his fabulous "A Short History of Nearly Everything," where he explains specifically what had to happen (and avoid happening) to make your existence today possible:
Consider the fact that for 3.8 billion years, a period of time older than the Earth's mountains and rivers and oceans, every one of your forebears on both sides has been attractive enough to find a mate, healthy enough to reproduce, and sufficiently blessed by fate and circumstances to live long enough to do so. Not one of your pertinent ancestors was squashed, devoured, drowned, starved, stuck fast, untimely wounded or otherwise deflected from its life's quest of delivering a tiny charge of genetic material to the right partner at the right moment to perpetuate the only possible sequence of hereditary combinations that could result--eventually, astoundingly, and all too briefly--in you.
So, here you are in 2016-congratulations! And you want to start a business (or so I'm supposing). This, then, is the time to get down to it. I should caution you that many people misunderstand what "starting a business" means. It doesn't mean betting [or mortgaging] the farm, telling your boss to "take this [day] job and shove it," or doing without health insurance. It means, if you do it right, starting small, working daily on business development and product improvement, and so forth.
Science teaches us that the best way to learn something new is to try it. Actually trying something new, failing at first, and getting the hang of it is really the only way to know that you're grasping the material in question. (Students who cram for an exam by reading and rereading material don't do as well as those who are able to take the exam, see how they did, and then re-take it.) The same is true with business. Reading and learning and studying are important-essential even, but until you try to put that learning to practical use, on whatever small and safe scale you want to start out with, you won't every fully understand the material you're trying to grasp.
It's time to test the waters by swimming in them, in other words. What's holding you back?