A teenager with "Benjamin Button disease" that has left her with the body of a 144-year-old has died weeks after her eighteenth birthday.

Ashanti Smith passed away on Saturday, July 17th after living with the rare premature aging condition Hutchinson-Gilford Progeria Syndrome, which saw her age 8 years for every single year of her life that she lived.

Heart failure and "natural causes" are the official causes of the young woman's death.

The teen's mom, Phoebe Louise Smith, celebrated her "brilliant and strong-willed daughter" who refused to let the disease affect her 'loud and beautiful soul.

Despite Ashanti sadly passing away just a couple of weeks after her eighteenth birthday, she was still able to celebrate turning eighteen in May with a night out with her mom and friends.

"There are photos of her first getting ID'd. We all took her out to the pubs, me and all the girls. We took her to 3 pubs... She got tipsy and she loved it," Phoebe said to the Daily Mail.

The teen passed away surrounded by close family, including her mom, her dad, Shaine Wickens, and a family friend, Kayleigh Cartwright. Her heartwrenching final words to her mom were: "You've got to let me go."

Phoebe said: "Ashanti's life was a joy. Even though progeria affected her mobility, it didn't affect anything else. She was a typical, stroppy eighteen-year-old and I loved everything about her. She was brilliant, she was gobby. She spoke her mind and everyone knew it.

"It didn't affect her heart, her willpower, or the way she felt about herself - she felt beautiful every day. I made sure of it every day."

Phoebe continued: "Everyone loved and adored that little girl. She touched their hearts so much with her willpower."

Despite her condition, she was so brave and determined to be treated like any other teenager.

In talking about how beautifully brave her daughter was, Phoebe said: "Her condition affected her mobility to walk as far. She had a broken hip and it had to be set back in three times, then eventually it came out again and she just walked with a broken hip.

"That child, my little girl, wouldn't get in a buggy. She'd either be carried or she'd walk. You'd ask if she wanted a drink, she'd say, 'I'll get it - what are you treating me different for?' She was very strong.

"It didn't affect her will. Obviously, it affected her mobility and she had heart disease."

Close family friend Katy also said a few words: "Her condition didn't affect her [mentally] at all. She was just, normal. She was like any other child. To be with her, she was just like everybody else. [On the outside] she was 100 and on the inside, she was eighteen."

Following her passing, the family set off 150 helium balloons for her and a £400 ($547.16) display of fireworks followed by 300 lanterns.

Her friends have set up a JustGiving page to help crowdfund for the "biggest, brightest send-off ever."

Phoebe said: "The funeral's going to be gay and BTS [themed]. She's having 4 pure white horses, with feathers and gay flags and BTS signs. Her coffins going to have BTS all around it and on top, it's going to be me and my 4 children in gay t-shirts.

"Ashanti was so proud to be gay. She was the proudest girl and she embraced the gay community. She loved it - and BTS. She's got about £5,000 worth of BTS goods in her bedroom which will always stay there. I'll put a lock on her door and let the kids sit in there. It's all BTS and gayness and I love it."

Rest in Peace Ashanti Smith. Thank you for brightening up the world for eighteen years and forevermore.