This Powell teen had trouble finding the perfect backpack. She and her mom formed a company and developed their own design.

Teenager Emily Laine Miller first dabbled in entrepreneurship as a third-grader, hawking homemade backpack keychains for a quarter. Now, the ambitious Olentangy Liberty High School junior is selling entire backpacks, through a company called Laine Avenue.

“The idea came up in a dinner conversation when I was 13 years old,” said Emily, 16, of Powell. “I thought, ‘What if I made something other than trinkets?' ”

She and her mother, Lisa Laine Miller, were tossing around ideas when Emily thought about all the issues she'd had with backpacks over the years. Some weren't roomy enough, some had straps that pinched or pulled, and none seemed to be ergonomically designed to accommodate heavy books without back pain. And so began a two-year quest to create the perfect bag, one that combined function, comfort and style.

Miller bought a used sewing machine on Craigslist and they began making prototypes. Emily's friends were invited to focus groups to air their gripes about backpacks and, eventually, try out the product.

Last year, Emily and her mom began selling the backpacks in limited quantities online—a soft launch to work out the bugs. One of the issues was the price—originally $88—that's now $58 to $68. In March, full-fledged selling began through laineavenue.com, with the help of Facebook, Twitter and Instagram.

The backpacks have wide, padded straps, a flat bottom and a squared-off top that makes them roomy enough for a day's worth of schoolwork as well as a laptop or tablet computer. Each comes with a fashion flap that zips onto the top. “Kids wanted something they could change up each year,” Emily said, so the company offers extra flaps ($18) in a multitude of colors, including one style that transforms into a cross-body purse.

Mom and daughter originally tried to make the flaps themselves, but quickly realized that, between Emily's classes and Miller's job—she's co-owner of the LaineGabriel marketing firm—they couldn't keep up. They farmed that work out to a Columbus company and hired a Johnstown business to manufacture the backpacks. The family funded the initial investment, an order of 1,000 bags. In late June, they placed a second order of 1,000 bags. Though the business isn't yet profitable (they declined to divulge financials), they're optimistic about the prospects.

While online sales are nice, the Millers also want to find “backers”—other teens who sell the backpacks in exchange for commissions. Backers also have access to an online Life Skills Academy that Lisa and Emily created, with lessons on subjects such as budgeting and time management.

Alex Phelps, 16, of Powell, said she signed up as a backer to make a little gas money. She's a close friend of Emily's and was part of the focus group that tried out the bag last year as a sophomore at Olentangy Liberty. She hadn't yet sold any as of early July, but hoped to attract interest through social media and her job as a lifeguard. “It's sturdier and bigger than other backpacks,” she said, but is not as bulky, which makes rushing through crowded high-school hallways easier.

Business-minded teenagers like Emily are becoming more common, said Greg Malkin, director of the nonprofit Young Entrepreneur Institute in Northeast Ohio. That trend is happening in part due to encouragement from more schools and organizations, he said. “Entrepreneurship teaches really good life skills,” said Malkin. “You learn self-confidence, how to take ownership of your life, how to come up with an idea and bring it to fruition, and how to fail. And it's a great way to learn grit and determination.”

The Internet has encouraged entrepreneurship by making it easier to find customers, Malkin said. “Now a lot of kids post Instagram videos, tweet and blog to build an audience,” he said. He knows an Ohio teen who sold homemade “slime”—made of glue, soap and a few other ingredients—through an Etsy store and shipped it around the world. “It's not going to be a business forever, but she's made thousands of dollars doing it,” Malkin said.

Not every enterprising teen becomes an adult business owner. Some sell a product while it's popular and then close up shop. Others, such as a Cleveland teen who made hundreds of thousands of dollars with a flower-arranging business, continue after high school, Malkin said.

For Emily, entrepreneurship is a family tradition. Besides her mother's marketing company, her father, Greg Miller, owns an architecture and engineering firm. She has no plans to abandon her business when she goes to college. Her younger brothers, Owen, 12, and Jacob, 8, want to pitch in more as they grow older, and her mother will continue to help. “I've learned so many things working on this,” Emily said. “The family connection is the strength I have.”