Mrs Boggiss said that in years to come there may be more of a gathering to mark the anniversary, but it was still too early for many.
"A lot of them are still dealing with it. Some of them are not ready to do the big gathering."
She said the accident affected everyone in different ways. Anna had struggled because the crash was basically like a war scene.
As one of the able-bodied people, she did not sleep for the next three days.
Mrs Boggiss said the accident remained an ongoing challenge for her daughter who was getting together with her "support crew" today.
Bethlehem Baptist Church which helped in the aftermath of the crash said it would be out today supporting those impacted by the tragedy.
Pastor John Elen from the Greerton Bible Church said church members who were part of the Johnston's extended family were offering special support today.
Meanwhile, the school's scheduled service trip to Kenya this summer was postponed although a private trip was taking place of many of the people involved in the crash. They left before Christmas.
College principal Eoin Crosbie said the trip was not associated with the school.
"The fact they are going to Kenya is for them to go there and probably bring some closure of things that have happened," he said late last year.
College board of trustees chairman Stephen Tetley-Jones said the school had gone through a period of grieving and healing.
The anniversary was not being officially marked by a gathering today because the school was closed for the holidays and it would have been difficult to bring the school's community together.
Mr Crosbie said it had been a difficult year for the school and the end-of-year prize-giving was used as an opportunity to offer some closure.
It was announced at the prize-giving that the family of Caitlin Dickson had created a service award in her memory to be presented each year to a student who reflected Caitlin's qualities.
The first recipient was Year 13 student Sarah Knapp who was also injured in the crash.
The college also named its rugby field Johnston's Sports Field in honour of Brian and Grace Johnston who were foundation parents of the school.
Details of what happened on that rainy day in Kenya were disclosed in the college investigation released two months after the crash.
It said that the group had set off from a visit to the Gavalagi High School at 1pm, following a heavy rainstorm.
It was still raining when a pre-arranged change of drivers took place 10 minutes into the journey, with student David Fellows replacing Mr Mmata. A few minutes later, the van rolled into a ditch.
The van, fitted with seats and seatbelts for 15 people, was carrying 17 people when the accident happened, with most not wearing their seatbelts.
Earlier reports detailed how by January 24, 13 of the uninjured and walking wounded had returned home, leaving six recuperating in Kenya until they were well enough to travel.
