"Now I'm thinking I should have been a lot more grateful for how it was going and it's really reminded me that I just need to trust what I've been doing and do what I can with what I've got," she said.
Boyle first announced herself with a brave fourth placing in the 800m, just 2s off bronze medal winner and world record holder Rebecca Adlington. It gave her a taste.
Three medals at the 2013 world champs confirmed her rise in status in the freestyle disciplines. There were gold and silver medals at the Glasgow Commonwealth Games in 2014 and last year, Boyle bagged silver medals in the non-Olympic 1500m, and the 800m behind the 19-year-old American phenom Katie Ledecky.
So she belongs, but knows the challenge that lies ahead.
"I've seen what times my competitors have been doing and they've been going really fast," she laughed. "It's not like I actively try and find all the information I can, but it's hard to avoid. Coaches and teammates talk about it.
"Katie's been doing fantastically. She's got an opportunity to do some serious damage in terms of gold medals and walk away as one of the best swimmers of all time. She's a great girl, and an amazing athlete, someone we can all learn from. She's got an open mind to what's possible and how her body works."
Boyle, 29, doesn't get bogged down about the clamour for medals.
"Nothing in life is that simple. There are so many people who are Olympic gold medallists and still unhappy with themselves. Winning a medal would be fantastic and a lifelong dream. At the same time there's 10 or 12 other women in my events who are capable of doing that. We just go and fight on the day and put ourselves out there."
So what is a good Olympics in her mind? "I'll be really happy if I finish having done best performances, swum faster than I've done before. Then I can also walk away with a feeling I gave it everything and really have no regrets." That said, Boyle looms as a royal prospect to be New Zealand's first Olympic medallist since Danyon Loader's double gold triumph in Atlanta in 1996. No pressure.