A determined 17-year-old girl is proving that you're never too young to make a difference and change the world for the better.

Shelby O'Neil is a young environmentalist who has written a dozen letters to company CEOs, urging them to stop using wasteful single-use plastic utensils - and a lot of them have listened to her.

After seeing California healthcare company Dignity Health run a commercial advertisement depicting people using plastic straws, Shelby wrote an email to the CEO explaining the dangers of wasteful plastics and why they should be eliminated.

The personal aspect of the email struck a chord with the company execs and they proceeded to drastically reduce their plastic usage. According to Mary Ellen Leciejewski, the vice president of corporate responsibility, the company has gone from using 8 million straws, plastic lids, and stirrers per year to 4 million. The utensils are now solely made available to patients in their 39-hospital system, rather than to visitors or cafeteria patrons, although the company says it is investigating using biodegradable alternatives.

"The fact that a 16-year-old girl had taken the action to write the CEO [was a powerful incentive]," Leciejewski told The Washington Post. "Maybe it was that it was a single person, one lone voice."

Dignity Health was just the beginning, too - Shelby also wrote letters to the CEOs of Alaska Airlines and Farmer Brothers coffee, both of whom responded to her personally as well.

Instead of dolling out 22 million plastic stirrers every year, Alaska Airlines started utilizing stirrers made from birch and bamboo. Farmers Brothers is set to start using wooden stirrers. Shelby also traveled cross-country to meet with Starbucks company officials - and earlier this month, the coffee giant became the largest retailer to announce their own phase-out of plastic straws, which is expected to save over 1 billion straws from landfills every year.

While these adults are particularly responsive to Shelby's outreach, she primarily started her environmental work amongst children. The teen from San Juan Bautista, California used the Girl Scout Gold Award project - which is the organization's highest honor - to start the Jr Ocean Guardians nonprofit that specifically educates children on the importance of ocean conservation.

Despite achieving these enormous milestones, Shelby says she is just getting started.

"I was never really scared of reaching out to companies, because someone needed to do it," she told The Post. "If no one else is doing it, then I'll do it."

Don't Let This Be The Last Straw: Share The Good News With Your Friends - Photo by Shelby O'Neil