President Jacob Zuma is among the guests that will bid farewell to "tiny giant" Ontlametse Phalatse on Friday morning.
The service is expected to start in her home town of Hebron, North West, at 06:30 on Friday.
She died on Tuesday, April 11, a day before her mother Bella and Zuma's 75th birthday. She suffered from progeria, a rare genetic disorder that causes premature ageing.
The 18-year-old was invited as a special guest to Zuma's birthday.
On the Tuesday, she went to town with her mother to see a tailor who was putting her specially-made outfit together. On their way home, she started having trouble breathing. She died of lung failure at the Dr George Mukhari Hospital in Ga-Rankuwa on Tuesday night.
On Wednesday, Zuma presented the family with a car, which had been one of Phalatse's wishes.
Phalatse paid Zuma a courtesy call on the eve of her 18th birthday last month, something which had been on her wish list.
"Ontlametse will be remembered for her sharp intellect, warm personality, brilliant ideas and her determination to use her condition to motivate others that they can achieve their goals regardless of any challenges," Zuma said.
He said he intended fulfilling his undertaking to ensure the Phalatse family got a house.
On Wednesday afternoon, hundreds of Hebron residents gathered at the Mmanotshe Moduana High School hall for her memorial service.