When it comes to unicorns, payments start-up Stax may be one of the rarest of the rare.

The Orlando-based payments start-up sits nearly 2,500 miles away from the tech incubators of Silicon Valley. And it’s a billion-dollar start-up run by a minority woman – 34-year-old co-founder and CEO Suneera Madhani, the daughter of two Pakistani immigrants – at a time when just a tiny fraction of venture capital funds go to women founders and people of color.

Madhani and her brother, company president Sal Rehmetullah, started Stax in 2014 as a payment platform for businesses that operates through flat-rate monthly subscriptions, rather than percentages of sales. Today, the company employs 300 people and has processed more than $23 billion in transactions for thousands of businesses over the past eight years.

But it almost never launched in the first place — and now, Madhani wants to encourage other women who look like her to take the leap.

“[I was] a reluctant entrepreneur,” Madhani tells CNBC Make It. “I was the last person to bet on me. And I think that’s the case for a lot of women.”

Growing up, Madhani personally witnessed the pain points of running a company. Her parents ran multiple businesses, from convenience stores to cafes, and she’s previously discussed how those ventures mostly ended in failure. (Madhani’s father, who died in 2020, endured a years-long bankruptcy struggle that ended in 2019.)

After studying finance at the University of Florida, the self-professed “data nerd” found herself working for a third-party affiliate of Atlanta-based payment processor First Data, selling payment terminals to business owners. Her parents’ business experiences gave her an idea: Some companies might prefer flat monthly rates over sales percentages. Depending on the client, her employer could potentially make more money, too.

Madhani pitched the idea to her bosses, who said no. Then, she pitched around it to “probably 12 different banks and processors,” she says, all of whom also said no. Giving her idea away — to a competitor, no less — was preferable to taking the entrepreneurial leap.

“I just wanted to be part of the process,” she says. “And to work for a company that believed in me.”

She soon found herself venting her frustrations at the dinner table in her parents’ house in Orlando, and recalls her father responding with some stark questions: “Why are you trying to give this away to everyone? Why do you need anyone?”

So, after building a basic payments platform and registering it with Visa and MasterCard, Madhani drove around Orlando in her Volkswagen Beetle, pitching her new company to other start-ups and small businesses. Ultimately, she signed roughly 100 clients — and won multiple local start-up pitch competitions, earning prize money worth roughly $200,000 in total, she says.

Over the next two years, the company raised $2.25 million from Orlando-based venture fund VenVelo. It wasn’t long before a larger rival came calling, offering $17.5 million to buy Stax, which was then known as “Fattmerchant.”

Madhani’s investors were adamant that she should sell. Instead, she says, she saw the buyout offer as validation that she was on the right path. Her company only had enough money to cover four more months of payroll at the time, she says, but she and her brother turned down the deal anyway — taking out a $500,000 loan to keep the lights on, instead.

Six months later, the company landed a $5.5 million investment from Atlanta-based Fulcrum Equity Partners. Today, Stax has raised more than $263 million in total funding, obtaining its billion-dollar valuation in March. (A company spokesperson says Stax “has a viable path to profitability,” but is currently focused on growing toward a future IPO.)

“I’m so glad we didn’t fold,” Madhani says of the 2017 buyout offer. “I look back at my 26-year-old self and I’m like, ‘Why didn’t I think that I could do it?’ I want to tell her, ‘You’re going to do amazing things. Just go for it.'”

Madhani can’t speak with her former self, of course. But she can advise other young women — which, she says, is why she launched a podcast and mentorship course for female entrepreneurs called CEO School in 2020.

Her lessons range from pitching start-up ideas and figuring out pricing models to maximizing profit and learning to be an effective leader. Her top takeaway, she says: Stop trying to be someone you’re not.

“I’m not your traditional CEO, and I was tired of trying to fit into this box that everybody wanted me to fit into,” she says. “There was a time that I was trying to fit into this world of fintechs, trying to fit into the boys’ club, until I realized I’m just not a man in a skirt. I had to authentically be who I was as CEO.”

In her early 20s, Madhani says, she rarely saw other women working in fintech — let alone as CEOs or start-up founders. She notes that it can be “lonely as a woman” in the tech industry, where less than a third of workers are women, and female leaders are few and far between. That lack of representation can make you doubt yourself.

“That’s why I believe representation matters so much,” Madhani says. “Because, as cliche as it is, seeing is believing.”

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