Lorraine Gallagher will make the heartbreaking journey to St Mary’s Church in Stranorlar, Co Donegal, for her elder daughter’s funeral.
It comes just six weeks after she travelled to the same church to bury her younger daughter Erin.
Both girls took their own lives in similar circumstances in recent weeks.
Last night, Ms Gallagher, 36, said she must remain strong for her girls and their brother, Seán James, 4.
“I know I have to be strong for my girls. They were strong girls,” said Ms Gallagher.
“I have to stay strong and to say one final goodbye to Shannon. I know she will be with Erin soon.
“The girls doted on Seán and I know they will want me to be strong for him and to help him get through all this.”
Ms Gallagher said people have been supportive of her family.
Hundreds of people, including many schoolfriends of Erin and Shannon, called to the family’s home in Ballybofey in the last two days as Shannon was waked.
“I wouldn’t have been able to get through this without the support and kindness of people,” said Ms Gallagher.
“I just hope that nobody has to go through what I am going through. I pray they don’t.”
The family’s solicitor, Patsy Gallagher, again appealed to the media to keep a respectful distance at today’s funeral.
“I would ask the media to be as respectful as possible under the circumstances,” said Mr Gallagher.
“This family are going through the most difficult time imaginable and they need space, respect, and dignity.
“We would ask the media not to be discussing or printing aspects of the family’s private life.”
Meanwhile, Fr John Joe Duffy, the priest who officiated at Erin’s funeral, is to conduct Shannon’s service. He delivered a hard-hitting homily at Erin’s Mass in which he appealed to young people to boycott social media sites.
He declined to comment on Shannon’s death.
There is always someone there to listen when you're ready to talk: http://t.co/HWiJ0J6G— spunout.ie (@SpunOut) December 13, 2012
However, it is understood his homily will again be of a powerful nature.
Shannon’s funeral Mass will take place at 11am at St Mary’s Church in Stranorlar for internment afterwards at Castlefin Cemetery.
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