Here’s a story familiar to many would-be founders: You got into the college you wanted. You got a good job. You were promoted faster than your colleagues. You were the youngest presenter at the important meetings. You decided to get an advanced degree, like an MBA.

Now, you are 10 years into your career, and you have an idea for a startup. You feel confident because you have enough experience to run a business and you are young enough to work long, demanding hours.

If many people can relate, then why are there relatively so few 30-something startup founders?

It is really quite simple: With all that success, it is hard not to become too comfortable and not want to take the risks that come with starting up.

Success Can Be a Bad Thing

When you’re successful in your twenties, you start making different decisions than a startup founder would. You buy the nice car you see your friends buying. You pick a nice house in a good neighborhood. You go to fancy restaurants and start to travel. You get married and maybe have a kid. After all, you are successful. Your friends at work are doing the same things.

The problem is, before you know it, you’re 30 years old with a killer idea, experience, and way too much overhead. You and your husband/wife can’t handle the idea of no salary or reduced salary. You already have mortgage, grad school and car payments.

Tom Kuegler from Wasabi Ventures calls this the Suckling Pig Theory. At least once a week, he talks to potential entrepreneurs who are too comfortable to leave their security behind.

So How Do You Take the Leap?

All is not lost. If you know your goal is to eventually launch a startup, you need to start preparing now. The medicine isn’t going to taste very good, but it’s pretty simple:

• Save your money — don’t buy that expensive car.
• Marry the right person. A supportive husband or wife can make or break a startup. Be upfront with them about your dream to be a startup founder. If they don’t run, they may be right for you.
• Before you make the leap, work at a startup. Big companies are not ideal breading grounds for potential startup founders.

Eventually, you are also going to have to work two jobs: your normal job during the day and your startup on nights and weekends. Do this for as long as possible to make sure your startup is worth the risk.

Starting Up Is Scary but Worth It

I know this story well because it happened to me. I was able to start Mosaic when I was 31. I had a mortgage, wife and a beautiful young daughter. I am happy to say that I am still married and now have two children. I drove a 2001 Honda Civic while my MBA friends got Audis.

I also got really lucky. I had some money from a previous startup that sold at the right moment. My parents helped financially, and with a lot of babysitting. My cofounder was ready to make the leap at that same moment. We lived frugally, and I gave myself a nine-month cushion with no salary.

The good news is that all of my experience came in handy. I was more efficient than younger CEOs. I also had more credibility with investors, who eventually wrote us large checks based mostly on the strength of our team. We monetized Mosaic early. My friends still have nicer cars, but I have my dream job. And I couldn’t be happier.

So don’t let your early success sidetrack you. You can start your dream company 10 years into your career and your company will be better for it.