The singer unveiled the complete lyrics to the emotional track three days before its big release, sharing that it's a song "I could perfect forever."
"These lyrics were written almost 2 years ago at the beginning of my ESV," she wrote on Instagram Aug. 22, referring to her latest album Endless Summer Vacation. "It was at a time I felt misunderstood. I have spent the last 18 months painting a sonic picture of my perspective to share with you."
While Miley believes her "work is done" on the ballad, she noted that it "will continue to write itself everyday."
"The fact it remains unfinished is a part of its beauty," the 30-year-old added. "That is my life at this moment ..... unfinished yet complete."
On "Used to Be Young," out on Aug. 25, Miley gets honest about leaving behind her former self. "The truth is bulletproof / There's no fooling you," the lyrics begin. "Me and who ya say I was yesterday have gone our separate ways."
The Hannah Montana alum also acknowledges becoming more mature in the song's chorus, with the lyrics reading, "You tell me time has changed me / That's fine, I had a good run / I know I used to be crazy / That's 'cause I used to be young."
The single comes five months after the release of Endless Summer Vacation, which contains her empowering breakup single "Flowers"—a song many fans have speculated to be about her divorce from ex Liam Hemsworth. However, Miley has since brushed off the rumors, telling British Vogue in a May interview, "I never need to be a master at the craft of tricking an audience. It will set itself on fire all by itself."
In fact, Miley—who was married to the Hunger Games actor for less than a year before he filed for divorce in 2019—said she initially wrote "Flowers" to be the "saddest song," but later put a more positive spin on it. "The song is a little fake it till you make it," explained the pop star, who was in a decade-long on-and-off romance with Liam, now 33, before tying the knot. "Which I'm a big fan of."
Still, that's not to say she regrets her marriage.
"I wouldn't erase my story or want it to be erased," she noted to the outlet. "Having an interesting life makes for interesting storytelling."
For more interesting facts about Miley, keep reading.