Jessica Mah, the founder and CEO of Indinero, was only 11 years old when she started her first business. Having learned how to code in fifth grade, Mah built websites for people and got paid a few thousand dollars a month.

Indinero CEO Jessica MahThat experience led her to do something more serious for her next business. She leased servers out of a few data centers and created a fully managed hosting service for small businesses, which she describes as a “cheaper version of Rackspace.” She had about four part time employees and generated six-figure revenues from it.

Although she had sales, Mah struggled to deal with cash flow and her server business eventually closed when she was 14 years old. By then, she was spending 40 hours a week on her business, and school was no longer a priority. Her grades were terrible and she ended up dropping out of high school.

“I was so stressed out,” Mah told Business Insider. “I remember thinking I was never going to start my own company and would never go into technology.”

But Mah was still smart enough to get into Simon’s Rock, an “early college” designed for students who want to get college education before graduating high school. It took her two years there to realize computer science was the only major she was happy with, and so, at age 17, she applied to UC Berkeley’s computer science program. After another two years, at 19, Mah graduated from UC Berkeley’s CS program.

Her time at Berkeley also brought back something she had been missing for a few years: her entrepreneurial drive. From her past experience running small businesses, Mah knew how the current accounting software were outdated. She knew accounting was an area ripe for innovation, but none of her fellow computer scientists were interested in the space because most of them had never dealt with it before. So by graduation, she created an accounting software called Indinero with her friend. “I wished there was some service like the ‘Google of accounting for small businesses,’” Mah says.

And the day after graduation, with a prototype, she headed down to Mountain View to join Y Combinator’s summer program. After 3 months, Mah raised $1.2 million for the seed round of Indinero. She was only 20 years old.

Indinero is a software that provides accounting, tax filing, and payroll management all under one service. It basically takes care of all the back office work by automatically importing data from the business owner’s financial accounts. It also has full-time professional accountants and tax specialists manually reviewing financial statements to make sure all the books are in order. “We just make it a lot more cost-effective and affordable because you have all these software layers doing so much of the work,” Mah says.

Indinero has been growing quite fast and now has 75 employees. It’s raised $8 million from angel investors, including 500 Startups’ Dave McClure, Yelp’s Jeremy Stoppelman, and Khosla Venture’s Keith Robois. Mah says over 500 companies use Indinero, including small businesses and bigger ones like some PR firms and law firms.

Despite all this success, Mah, now 24, says running a company has been a big challenge for her. “It’s my first company that’s doing millions in revenues, my first company that has full-time employees and a full office…So it’s been pretty difficult,” Mah says. But she still thinks it’s all worth the struggle. “It’s challenging at times. But it’s an incredibly rewarding job.”

This story originally appeared on Business Insider. Copyright 2014

VentureBeat's mission is to be a digital town square for technical decision-makers to gain knowledge about transformative enterprise technology and transact. Discover our Briefings.