It will be the first time Flora Stewart-Sandeman has run a 26.2-mile race.
And she is kicking off her marathon-running career with the most high-profile race in the world.
Her efforts will raise vital funds for a charity close to her heart.
Miss Stewart-Sandeman, who studied at Thomas Alleyne's High School and Oldfields Hall Middle School, both in Uttoxeter, now works as a professional development trainer in London.
Since moving to the capital, she has been "shocked" by the scale of homelessness there.
And the 24-year-old has already raised £750 towards her target of £2,500 for housing charity Shelter.
This April, she will join around 40,000 of runners from around the world, as well as the sport’s elite athletes.
The race takes in landmarks such as Big Ben, St Paul’s Cathedral and Buckingham Palace.
She said: "I've been doing a lot of training for it, but I'm building up to doing the full Marathon. The idea is that I peak on the actual day itself.
"It is daunting, but I've had so much support from my family and friends, and knowing there's so many people behind me willing me on will be a massive boost for me.
"Since moving from Staffordshire to London, the scale of homelessness just really shocked me.
"I used to think that homelessness wasn't really a problem in places like Uttoxeter, but since I've learned more about it I've realised the majority are always hidden homeless – sleeping on people's sofas or living in sub-standard accommodation.
"Homeless people are some of the most vulnerable and excluded people in this country, and the rates of mental health problems are heartbreaking.
"In 2016, around 32 per cent of people reported having a mental health problem, according to Shelter, which is around 10 times higher than the national average.
"Psychological issues such as trauma, substance misuse and social exclusion are also common."
Miss Stewart-Sandeman has run several races around the area, including the Abbots Bromley 10k, and a British Heart Foundation half-marathon at Blenheim Palace.
She said: "I've always had a real passion for running, and the marathon is just the pinnacle of that really.
"A lot of people wait years to get a place on the London Marathon, so when I found out I was lucky enough I just couldn't believe it."
To donate to Miss Stewart-Sandeman, click here