Lexie Alford's impressive achievement was completed on May 31 when she set foot in North Korea, the 196th sovereign nation on her list, the news sites report.
Alford is set to beat out the current Guinness World Record holder James Asquith, who was 24 years old when he finished visiting every country in 2013.
Alford has tracked her journey on social media, amassing over 73,000 followers on Instagram.
"OFFICIALLY TRAVELED TO EVERY COUNTRY IN THE WORLD," she wrote along with a photo of her in North Korea. "it's crazy to have years of hard work culminate into one single moment. I'm so grateful to everyone that's helped me get here. The greatest chapter of my life is coming to a close. Cheers to a new beginning"
OFFICIALLY TRAVELED TO EVERY COUNTRY IN THE WORLD🌍🤯 ⠀⠀⠀⠀⠀⠀⠀⠀⠀ it’s crazy to have years of hard work culminate into one single moment. I’m so grateful to everyone that’s helped me get here. The greatest chapter of my life is coming to a close. Cheers to a new beginning 🎉⠀⠀⠀⠀⠀⠀⠀⠀⠀ ⠀⠀⠀⠀⠀⠀⠀⠀⠀ Photos by @thomasbrag
In an interview with Forbes, Alford said her love for travel began at a young age thanks to her family owning a travel agency in California.
"My parents would take me out of school and place me on independent study for weeks and months at a time every year," she said. "My parents placed a lot of importance on exposing me to every way of life around the world, and that had a very profound impact on the person I am today. I've always had a curiosity about other people's ways of life and how they find happiness."
In order to become the new Guinness World Records title holder, Alford told the news outlet she has to submit nearly 10,000 pieces of evidence of her travels in chronological order.
What's next for the young traveller? She says she's writing a book about her experiences and is going to start public speaking.
"After finally completing this massive life goal, I'll be taking the next few months to nourish my physical and mental health as I make plans for the future," she told Forbes.