Every entrepreneur reaches a point of no return, a moment when you suddenly realize you're absolutely committed--perhaps even overcommitted--to a new venture. For me, this moment happened last fall, three or four months into launching our company, Iodine. I was due to meet with a potential investor in Silicon Valley, and before jumping in the car, I stopped by the local juice shop to buy a smoothie.

By all accounts, this was a routine smoothie--mango, ginger, and carrot, $6.99. Certainly, when the clerk put the full plastic cup glowing with orange goodness on the counter, it looked like every other smoothie I'd bought there. But when he rang up the till, I pulled out my wallet and realized I had no cash. No worries: I offered my debit card. It was denied. As was my Visa card. And my American Express card. I was flummoxed. This smoothie, it seemed, wasn't so ordinary. This smoothie was, in fact, a fruit-flavored epiphany: I had no liquid assets, had maxed out my credit cards, and had put everything I had into the new company. There was nothing left in the bank. I was tapped out and felt utterly insolvent in a way I hadn't since my grad-school days.

The crisis was quickly averted: I dashed back to the office, borrowed 20 bucks from my co-founder, Matt Mohebbi, and paid for the drink. But as we drove down 101 to Menlo Park, Matt and I realized that this smoothie marked a turning point. Without quite realizing it, we'd gone further, had become more committed, and had even more riding on this new venture than we'd bargained on. (And later that afternoon, I swallowed hard and liquidated a chunk of savings, enough to keep my family fed and to splurge on the occasional beverage.)

We have taken to calling these "smoothie moments": those unexpected reminders that we're in deep, way deeper than we ever expected to be, and that it's so, so new. Launching a startup, it turns out, is more about learning than it is about knowing.

I'll be the first to say I should've known better. After all, I had spent more than a decade as a lead editor at Wired, where we prided ourselves on having an umbilical connection to Silicon Valley. Friends, neighbors, and colleagues had all done startups. Surely, I knew what was in store.

Turns out, not so much. As seems obvious, reading Steve Jobs doesn't make you Steve Jobs. It's one thing to report on startups and innovation and entrepreneurship, and quite another to attempt them.

Fortunately, most of the mistakes so far have been fairly bearable smoothie moments: small embarrassments that were readily navigated and often enlightening. Even the more egregious miscalculations have turned out all right (such as the time the wire for our first angel investment reached our bank account exactly 19 minutes before our payroll withdrawal hit, just covering the difference). No doubt, there will be more close calls and some outright blunders ahead. But that's part of the thrill of this--being a bit out of our depth, learning on the fly.

You can fill a Kindle with management books and lean-startup manuals, but the reality of building a company is writing your own playbook and adapting that playbook to the obstacles--many of them self-inflicted--that inevitably emerge.

There's no way to avoid mistakes entirely, nor should you want to. Smoothie moments are part of your startup story. They will become the adventures you'll share on the eve of the IPO, the look-how-far-we've-come tales you'll tell when signing the big acquisition deal. They are the turgid passages we'll recall when we've steered our way to different waters and can't believe how we've managed to make it so far.

From the May 2014 issue of Inc. magazine