Paula McGuire was once too afraid of the water to walk down the steps into the shallow end of a pool.
Now she is to embark on a challenge to become the first person to swim round the coast of mainland Britain.
The 36-year-old, from the east end of Glasgow, describes herself as a recovering aquaphobe and "basket case".
"I am someone who has had a lot of problems with social anxiety and mental health," she says.
"I used to be so terrified of failing that I just wouldn't try anything."
Task One - Learn to ride a bike
But something changed when she turned 30 - a realisation that unless she did something, she might continue life as a "functioning recluse" for another 30 years.
The first fear she decided to tackle was learning to ride a bike.
By all accounts it wasn't pretty. Paula left her first adult class knee deep in bruises.
But she stuck at it, and eventually she was able to triumphantly cycle round Glasgow's Sir Chris Hoy Velodrome.
In a campaign she named "Paula must try harder", she had a go at all 17 sports featured in the Glasgow Commonwealth Games.
After the games, she kept setting herself more challenges - from stripping naked as a life model for an art class and flying a jet to simply shopping on her own.
"Everything over the last few years has built me up to this point," she says.
"Now I know that the only thing that will make me fail is if I stop trying."
She admits her latest challenge to swim from Land's End to John o' Groats and back may seem "a bit ridiculous since I've only recently learned to swim".
Over about five months she plans to cover 1,800 miles, swimming for six hours at a time, sometimes starting in the middle of the night to beat the tides.
"But I've no doubt that I'll do it," she says.
"With the right attitude and support, I'm a firm believer that we can achieve incredible things."
As someone with a fear of water who has learned to swim, Paula perhaps knows this better than anyone.
She describes the process as the equivalent of "trying to learn to knit while running away from a bear".
"When I was being instructed I couldn't really take anything in," she says.
"I would be shaking, I could randomly burst into tears.
"My head would be going a million miles an hour, and I would be trying to calm my body down."
Over time she developed coping mechanisms.
She learned to focus on her breathing and to "connect" herself to things around her by naming things she could see, hear and feel.
In true Paula style, she just kept trying and it paid off.
"Thinking back, I couldn't even stand in the water, I couldn't even get near a puddle without breaking into a sweat," she says.
"But now it's where I go when I want to relax, it's my place of peace.
"There's nothing quite like moving through the water under my own steam, putting one arm in front of the other- it's almost dreamlike.
"Even though I do still have mild panics in the water, it is a place of comfort for me now."
'I will succeed'
Next May she will step out of her comfort zone once more, and wade into the water at Land's End to start her challenge.
Paula hopes to raise awareness about mental health, and to show people who have these issues that you can still have a fulfilling life.
"Looking ahead to next year, I know that there will be days when I am exhausted and the fear will take over," she says.
"But as long as I keep trying and keep swimming I know that I will succeed."