"You never know when your time's going to come. You have to cherish every moment," she wrote.
Just 10 days later, 22-year-old Shiloh died after being struck by a car that plowed into a power pole near where she was standing in Burnaby, B.C.
Family and friends of the two young sisters from Coquitlam, B.C., are in shock that the "inseparable" pair died within days of each other.
Their cousin, Janica Lucas, said the duo were roommates, and Shiloh was heartbroken after her sister died on Feb. 7 of yet-to--be confirmed causes.
"It turned her world upside down," Lucas said Thursday. "This person she loved so much was gone. She didn't know how she was going to be able to cope with it."
"I think for that reason it's kind of a blessing that she didn't have to suffer for that long. They were only apart for 10 days."
She said Shiloh took time off to grieve, and was just returning to work on Feb. 17, when she was killed while she stood on a street corner on Canada Way near her workplace.
RCMP have said a white car collided with a grey Volkswagen before skidding along the centre median, crossing two lanes of traffic, crashing into the power pole and hitting Shiloh.
A celebration of Keziah's life on March 7, which Shiloh had been helping to plan, will now be a joint ceremony for the sisters.
Keziah had recently finished an esthetician course, and Shiloh worked at a tile store while pursuing her dream of becoming an artist. The older sister was also a devoted church-goer, who suffered with chronic pain from Crohn's disease.
"She was in a lot of pain, but you would never know it. She always had a smile on her face. She was always super happy and bubbly," Lucas said.
"It was a really unique bond. They just loved each other so much and were so grateful they had each other. They'd overcome lots of struggles, both of them."
Their mother, Jacquie Johnston, flew to Mexico to grieve after Keziah's death but will return to Canada on Friday, Lucas said. The sisters had no other siblings.
"She's completely in shock," Lucas said of the girls' mother. "She's coping as well as you possibly could in a situation like this."
Amanda Masih, Shiloh's best friend, said Shiloh was a "bright light" in the life of everyone she met.
"This girl was definitely an angel. I've never met anyone in my life like her before," said 28-year-old Masih.
An online fundraising campaign has been set up at gofundme.org to create a memorial bench to honour the sisters. More than $3,500 has been raised so far.
RCMP are still looking for witnesses to the crash that killed Shiloh.
— By Laura Kane in Vancouver