Mason felt she was in the form of her life when New Zealand went into Covid-19 lockdown a year ago but the forced isolation and travel restrictions meant all her plans went out the window.
After running a personal best of 2:38:35 at the 2019 Sydney Marathon, the 33-year-old doctor from Tauranga intended to only work part time in 2020 with the aim of heading overseas to compete in events to realise her dream of getting to the Olympics.
Fortunately she was able to run and win the Rotorua and Auckland marathons in late 2020 and she feels very fortunate to be in the position she finds herself in still attempting to get to Tokyo.
In June, Mason changed coaches and now comes under the guidance of Craig Kirkwood, a former top runner himself, who also looks after Olympic 1500 metre qualifier Sam Tanner and triathlete Hayden Wilde.
She says the goal on Sunday is to run fast enough to qualify for Tokyo."This is probably the one chance, I've really got to do it by the end of April to show the selectors and we decided that Christchurch was the best option, so this is it really."
"Since my last really fast race (Sydney 2019) I've just been building and building, I've not had any injury disruptions and I would say I'm in better shape than I was a year ago."
Mason admits it's hard to exactly gauge her form because the Rotorua and Auckland course are a lot slower, but says her training suggests that she's in good shape.
"The pace I can run and sustain is faster than probably what I could do a year ago and Craig can take credit for that and so it's sort of stretching out the limits of the pace I can run at."
She says being a part of a bigger training squad in Tauranga has also helped.
"The downside of Covid is that people couldn't travel overseas but the upside has been that everyone has been in New Zealand training and in Craig's group on a Saturday morning we'd have 20 to 30 runners doing different distances and paces and everyone is supportive, which is cool."
Mason says Covid and the postponement of the Olympics certainly dragged things out a lot, but a change in coach has been really positive for her mentally.
"Having slightly different workouts, different people to train with and different challenges has kept things exciting while we haven't had those big races to aim for."
"I think I've only gained strength and fitness and endurance over the last year so I'm probably going in with a better shot now than I was a year ago so it's possibly worked well for me."
However Mason is still nine minutes away from the automatic qualifying time, but feels Sunday's Christchurch marathon, which is the fastest in New Zealand, gives her the best opportunity.
"It's a long shot, but it's good to be going in with no real expectations to do it, but you might just surprise yourself and that's how I roll."
"A marathon is such a mental challenge that if you can get to the end and you've stayed tough and felt like you've given it everything then I don't think you can ask for much more than that."
Mason won't be on her own in Christchurch with Kirkwood and training buddy Wilde both taking part with the intention of trying to help with the pacing.
"I'm pretty hopeful there'll be people around that are all sort of aiming for the same time and it's so much easier running in a group in the marathon."
Mason is hoping for good conditions on Sunday saying she's still a little scarred from two years ago when there was torrential rain, wind and was freezing cold.
She is one of more than 4000 runners lining for the Christchurch marathon on Sunday morning.
