The inspiring Australian will test herself over the 3.8km swim, 180km ride and 42.2km run, that makes up an Ironman triathlon.

It's been a long road to get to an Ironman after she was caught in a fast-moving bushfire in Western Australia in 2001 where she suffered burns to 65 per cent of her body.

And on Sunday, that rehabilitation process will be complete when she jumps into the water early in the morning.

"It was the challenge I set for myself years back when I was in hospital," she said.

"I guess I used it as a motivator to keep improving and getting better and it's come around so fast and come Sunday, I'll have all this free time on my hands."

Not only did the bushfire almost claim her life and leave many lasting effects, she also had to learn to walk again. She admits the training for Ironman has been "hectic".

"Maybe not hectic for anyone who does triathlons, but because I didn't come from that sort of background I had to learn how to master swimming and cycling and running ... I found that pretty hard and time consuming," she said. "Learning how to walk again has been the hardest part about the journey, there's no doubt about that.

"That was really hard because I realised how long the recovery was going to be."

When asked if she saw herself as a person other people could look up to, Pitt was typically humble.

"If people see me as inspiring, that's a really good place for me to be in and I'm really grateful for that.

"I try to be more grateful for things I have in my life and I'm excited about Sunday, but I'm also anxious and nervous and a bit unsure," she said.

"I'm just living my life as best I can and if people get inspiration out of that, that's fantastic and I'm really happy.

"My advice to anyone would be to challenge yourself and step outside your comfort zone because that's a place where anyone can really grow."

After coming up to Port last month to have a look at the course she would be doing, Pitt said one lasting effect was the Matthew Flinders Hill.

"I came up here a few weeks ago and did it and it's pretty hectic," she said. "I'm just focussed on Sunday at the moment and then I'll see what happens next."

Pitt is also raising money for Interplast - an organisation that provide reconstructive surgery to people who desperately need in developing countries and it is a cause close to her heart.

To donate, visit ironman.gofundraise.com.au.