Image copyright Me & The Bees Image caption Mikaila Ulmer first set up the business when she was just four years old

The BBC's weekly The Boss series profiles a different business leader from around the world. This week we spoke to Mikaila Ulmer, the 13-year-old chief executive of Me & The Bees Lemonade.

Mikaila Ulmer's lemonade is now stocked in more than 500 stores across the US, but unfortunately she has slipped to a "C" in her maths class.

Running a successful business is very much a full-time job, but Mikaila - the founder and boss of Me & The Bees Lemonade - also has to make time for her school work.

Just 13 years old, one day she will be in class, the next she could be speaking at an entrepreneurship conference.

"It is not the easiest, that is for sure," she says.

"Sometimes I have to miss classes to do an interview, or travel for a TV show. Or I'll miss a big show or presentation because I have a large project or test at school."

Now selling 360,000 bottles of her lemonade a year, with stockists including upmarket supermarket chain Whole Foods Market, Mikaila is one of the youngest business owners in the US.

Image copyright Me & The Bees Image caption The lemonades come in four flavours, but all contain honey

Yet while she only recently became a teenager, she has actually been running her Austin, Texas based business since she was four.

With the continuing help of her parents, Mikaila first started selling her lemonade in 2009. That year she set up a table in front of the family home, and began selling lemonade based on a 1940s recipe from her great-grandmother.

The recipe contains honey, and around the same time Mikaila got stung by two bees in two weeks.

Her mother and father advised her that rather than freaking out at the sight of every bee, she should do some research to better understand them, and the crucial role they play in pollination, and the wider ecosystem.

This inspired Mikaila to give some of the money she raised from the sale of the lemonade to organisations that protect honey bees.

Soon the business was supplying a local pizza shop, and it has grown since then, with 10% of profits continuing to be donated to bee conservation groups.

Image copyright Me & The Bees Image caption Mikaila has gone from being scared of bees to giving 10% of her profits towards their conservation

But with Mikaika's mother, D'Andra, and father, Theo, actively involved in the business, it begs the question - who is is actually in charge?

"It was all me at the beginning, squeezing the lemonade at my stand, but then my parents designed some nice stickers for the cups," says Mikaila.

"As the business got larger I had to say, 'I can't do this alone.' That's when I had to start asking, 'Mom, Dad, how do I get a logo? And into a manufacturer? And more stores?'"

The fact that both parents have business school degrees certainly must help, with D'Andra having a background in marketing and sales, and Theo in business operations.

Yet D'Andra says that she and Theo had "zero" experience of the food and beverage sector.

Mikaila says it is all about teamwork.

"We're considered co-CEOs, because I make decisions that my parents wouldn't make, and my parents make decisions that I wouldn't make," she says.

"Also, I am young... I know I don't know everything, and so I am definitely going to take their advice and opinions into consideration."

Image copyright Me & The Bees Image caption Mikaila's mum and dad help her to run the business

The big breakthrough for the business came in 2015 when Mikaila was nine. At the start of that year it won the contract to supply Whole Foods Market.

"Mikaila and her company caught our attention on a number of fronts," says Whole Foods Market's Jenna Gelgand.

"She had a unique product that tasted great, along with a strong, passionate founder and social mission.

"We were immediately impressed with Mikaila as a young entrepreneur, and with her vision to create awareness around the importance of pollinators."

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Later in 2015 Mikaila was introduced to TV viewers across the US when she appeared on entrepreneurship show Shark Tank (the American version of UK programme Dragons' Den).

Her pitch to a group of potential investors was good to enough to persuade one of them - Daymond John, boss of clothing firm FUBU - to invest $60,000 (£46,000).

Two years later, a consortium of former and current American football players invested $800,000.

Image copyright Getty Images Image caption Mikaila regularly speaks at business and charity events

Mikaila continues to win numerous awards for young entrepreneurs and African-American business owners, and she has been praised by former US President Barack Obama.

When he was still in office he invited her to the White House in 2015, and a year later she introduced him at a women's summit.

Geoffrey Soares, owner of Summit Beverage Group, which started bottling for Me & The Bees Lemonade last year, says that Mikaila is a very strong brand ambassador.

"You can have a great product, but if you don't have a great story, how are you going to get noticed? This is a really tough industry," he says.

"Without Mikaila, I would question how they would break through. She is very important, but at the same time everyone needs help - they are a good family, and they are committed to building something."

Image copyright Getty Images Image caption President Obama called Mikaila "an amazing young lady"

Mikaila says she now hopes to launch additional businesses, but school is also on her mind.

"I want to start new companies - to me having one company gets boring sometimes," she says.

"I like coming up with business names and new logos to design, that's the most fun bit for me. I'm also nervous about high school, but looking forward to making new friends and not wearing a uniform."