As a member of Girls' Generation, one of K-pop’s most popular groups, Stephanie Young Hwang — who performs as “Tiffany Young” — has had a part in 15 albums, 16 chart-topping singles and about 1.8 billion views on YouTube.

But Hwang, 29, had always wanted a solo career, and when the group’s contract ended in 2017, she decided it was the best time to take a hiatus from it and return to the United States. Her groupmates understood, she said.

“I’m proud to say that Girls’ Generation — that over 10 years and our discography — it was always about growth,” Hwang told NBC News. “Between the girls and I, we had this trust where I said, ‘Yeah, if you want to put a Girls’ Generation project together. That’s always going to be something I want to do, so let me know.’”

Thus far, Hwang has been happy with her decision. She released her debut EP, “Lips on Lips” on Feb. 22 and the record hit No. 2 on iTunes’ U.S. pop chart.

“I can’t believe it is what it is right now,” she said. “I’m still in shock but in a good way.”

Born in San Francisco, Hwang grew up in Southern California. She said living with her parents, sister and grandparents gave her a “good mix” of American and Korean culture. She remembers going to sporting events and Disneyland, and mainly speaking English with her dad as her mom taught the children cultural traditions and spoke Korean.

After the death of her mother when Hwang was 12, followed by the death of her grandfather a year later, she found comfort in music. At 15, she decided to move to South Korea, joining SM Entertainment, which has produced K-pop acts such as BoA and SHINee.

“Losing your mom is something you go through once,” Hwang said. “At such a young age, I was in a place where nothing made me happy. I felt nothing, and I was just feeling like nothing mattered to me at all until I started singing.”

“That’s why music was such a big thing for me,” she added. “I was very sure, even at such a young age, that nothing was making me feel better than this.”

Adjusting to South Korea was difficult. Not only did Hwang have to deal with being diagnosed with scoliosis at 16, but she also had to relearn the language her mother and grandparents would speak with her at home. Her relationship with her father also became strained, Hwang said.

“Being 16 and 17 was a very tricky time,” she said. “I remember having my dad call and discuss really, really heavy and heated issues and then having to go back on set and back onstage or shoot another video.”

But the experience helped her mature and fueled her songwriting for the new EP, Hwang said. While her single, “Born Again,” discusses her rebirth as a new solo artist and being more authentic, “Not Barbie” is dedicated to “anybody who doesn’t feel like they belong.”

“There was a time where I was so lost in that and I forgot how that takes a toll on your emotions and your mental health,” she said. “Oftentimes in Asian culture, you’re not allowed to talk about your flaws so openly. And I never wanted to hurt anybody or affect anybody through my personal life.”

“It came to the point where that was part of my story,” she added.

Support from her fans and family — including her aunt and sister — helped give her the confidence to tell those parts of her story on the new EP, Hwang said.

She’s also glad that her relationship with her family has improved since she’s back in California. And to make her return even sweeter, “Lips on Lips” tells both her story and that of her sister.

“It’s incredible to hear when your older sister says, ’Man, you wrote the soundtrack to my life,’” Hwang said. “And I’m just so happy that I get to heal her heart through this.”

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