FORTUNE — Dear Annie: I’m a brand new college graduate and, although I have one job offer from a big company (after interviewing with many), I’d

really rather work for myself. For the past couple of years, I’ve been earning “mad money” by selling handmade jewelry online, and it’s been going well enough that I think it would really take off if I do it full-time.

On the plus side, I have no student loans to pay off and my expenses are minimal because I can live with my parents while I build the business. On the other hand, my mom and dad are urging me to take the “real job” because, according to them, starting a business right out of school is crazy. What do you and your readers think? — Mary Ann

Dear Mary Ann: Far be it from me to contradict your parents, particularly since they’re evidently trying to spare you what could be a painful disappointment.

“The Mark Zuckerbergs of the world make startups look easy, but the cold hard facts are that 9 out of 10 new businesses fail in the first five years,” notes Carol Roth, a Chicago-based business strategist who has helped her startup clients raise over $1 billion in capital. Roth also wrote a New York Times bestseller, The Entrepreneur Equation: Evaluating the Realities, Risks and Rewards of Having Your Own Business.

Before you make up your mind about which way to go, Roth says, take a hard, honest look at your motivation for starting a company. Too many entrepreneurial wannabes of all ages (not just new grads) are “looking to get rich, escape the corporate grind, and work shorter hours with more free time,” she observes.

None of those reasons is likely to lead to success. What will? Says Roth, “If you’re focused on solving a customer problem or need, believe you can do what you do better than anyone else, and you’re dying to work long hours, wear many hats, and juggle endless responsibilities, you have the right startup mindset.”

According to Susan Spencer, you also need certain personality traits. One of them is a willingness to work very hard all by yourself, at least for the first year or so (and possibly longer).

An attorney and former general manager and part owner of the Philadelphia Eagles, Spencer also launched two thriving businesses and wrote a book called Briefcase Essentials. “Many young entrepreneurs fail because they take on employees, which means overhead, too quickly. The less financial pressure you put on yourself at the outset, the more likely you are to succeed,” she says.

The downside: “Doing everything yourself — selling, keeping the books, paying the bills, and so on — for 10 or more hours a day is a lonely existence, and it takes extraordinary drive and determination. It’s not for everyone.”

With that in mind, are you sure you want to leap in head first? If not, Carol Roth has a suggestion that might please both you and your folks: Get a job in the industry where you eventually want to establish your business as a way to learn “how to manage vendor relationships, market your product, deal with customers, and keep detailed books.”

While you’re soaking up all that real-world knowledge, you can continue to sell jewelry online in your spare time, doing what Roth calls a “jobbie” — a cross between a hobby and a job — that “lets you explore how viable it really is while getting paid by someone else.”

If, however, you’re determined to start your own business right now, without easing into it by getting more experience first, you’d be smart to reach out to a network of fellow fledgling business owners for advice and support. Roth recommends a nationwide group called the Young Entrepreneur Council, which “offers good tools for recent grads looking to create a startup.”

You can also seek out more seasoned mentors, Susan Spencer says. “Find a few successful entrepreneurs to be your informal advisory board,” she suggests. “They can be a great sounding board for your ideas. They can also help your business grow faster by, for instance, introducing you to bankers.”

Spencer points out that this very early stage in your career could be a good moment to start a business, for a couple of reasons. First, your tolerance for risk is greater now than it may ever be again (especially given that you have no student loans and minimal living expenses).

“Before you take on responsibilities like a mortgage and kids, give this your best shot,” she says. “As long as you’re going into it with your eyes wide open, you are unlikely to regret it.”

That’s partly because having run your own show “can be a stepping stone to a great job if you decide to change direction later on and go to work for someone else,” Spencer notes.

“I’ve always hired people who had started their own companies. It gives you a kind of business education that you can’t get in any other way.”

Talkback: Does it make sense to start a business right out of college? Why or why not? Leave a comment below.