"Since I decided to fundraise, thinking about the reason I'm fundraising and all the people who have donated makes me motivated to train harder."
Many people who had pledged money online were family and friends, donating between $20 and $100.
Organisers said many runners like Allum were using their marathon journey as a chance to raise awareness and money for charity.
Allum, in her third year of a Law and Commerce degree at Victoria University, has run smaller events in the past, including two half-marathons, but some sound advice was close at hand.
Her parents Chris and Deb Allum will be with her at the start line and are both attempting their 15th marathon, which means they have now joined what was called a "Survivors Club".
In the 55th running of the Rotorua Marathon, 564 people are in the Survivors club, although 45 members had died since its inception.
The original plan was to reach the milestone at the same time their daughter was attempting her first marathon, then Casey decided to use the challenge as a way to raise funds for Lifelife.
Casey's fundraising page link is rotoruamarathon2019.everydayhero.com/nz/casey-rotorua-marathon-lifeline-fundraising