Kim So-hyun travels to the United States alone for the first time through the Lifetime channel entertainment program Because This Is My First Twenty.
 This program features Kim So-hyun's journey as a TV personality, a global star, a 10-year-old actress, and a 20-year-old woman to find her own identity. Filming began in August 2018. A press conference was held at Four Seasons Hotel in Seoul on September 28, 2018.
 At the beginning, Kim So Hyun struggled packing for her first trip to the United States. She brought a skipping rope that didn't need for a trip, lactic acid medicine, and acupressure massage tools. In addition, she brings along her scrapbook that contains various information for the trip and check her bucket list in the car.
 Kim revealed that she usually wears comfortable clothes; tracksuits. So, Kim made a surprise encounter with world-famous fashion influencer, Aimee Song to receive fashion tips from her and recommends the perfect style for Kim. As soon as they meet Kim So-hyun and Aimee Song, showed their heartwarming chemistry by continuing the relay of praise and letting Kim try. Kim was surprised to see Aimee Song's closet reminiscent of a department store with many fashion items and costumes.
 Aimee Song guides Kim So-hyun to a Mexican restaurant. Kim showed her unique charm from mukbang to shopping at a famous vintage shop in Beverly Hills, Los Angeles, to showcase a unique fashion that maximise the charm of a 20 years old Kim So-hyun. The meeting between Aimee Song and Kim So Hyun has been publicized on Instagram Live before broadcasting to show Kim's styling transformation.
 Kim So-hyun visited Instagram Headquarters in Los Angeles and having a good time meeting with Jiffpom, a World SNS star dog who has eight million followers.
 Kim So-hyun visited the place where the Academy Awards ceremony is held and leave a surprise video letter to national actors Lee Byung Hun and Ahn Sung Ki. The 20-year-old Kim So-hyun, who visited Hollywood at the Holy Land of the film revealed her aspirations as an actor. She also shows the foreign fan who she met by chance with fluent English and fan service.
 Kim So-hyun demonstrates her reverse self ability by attempting a self show at a street art on Melrose Avenue where American fashion people gather.  She visited a company of fashion world famous boss, Chriselle Lim and photographers from Insa and they gave honey tips for life.
 Kim So-hyun arrived at a famous hand made burger in the American West since 1952. Then, she went to Joshua Tree National Park, Salvation Mountain, the Mojave Desert and Seven Magic Mountains.
 Episode quote: "You learn as you try"
 Kim also challenged her first camping under the stars for her bucket list. She also showed her cooking skills by roasting the meat alone with confidence and even tried doing the "Salt Bae" way of sprinkling salt on to the meat. She then revealed her struggles in her acting career and living as an actress.
 Episode quote: "When you are acting or living as an actress, there is nothing tangible that you can grab. You are not doing it to hold onto something, but for that intangible something that you cannot hold, you have to continue walking and go through the process of going forward."
 Kim So-hyun visits Fremont Street, one of the top three major night view attractions of Las Vegas. Kim then challenged herself to the Las Vegas specialty zip-line. At the ending of the episode, Kim shared a video letter to friends who are about to become twenty years old. Kim So Hyun, who was worried about her first solo appearance in her debut 10 years, shares her impression that she discovered the 'twenty years old Kim Sohyun', which she did not know through her travels.
 Episode quote: "Rather than fearing, take action. You can still take away something from the process even if you fail. Through that process, you will become more mature and through such process, you become happy."