The Otago Polytechnic student said she was "stoked'' to have the surgery before Christmas, several months earlier than expected.
"It was a huge shock getting the call... It's a Christmas miracle.''
More surgery was needed, including tattooing a nipple on her new breast and resizing her other breast, she said.
The surgery on Monday went well and she felt some normality had returned to her life.
Before she was anaesthetised, she bid goodbye to her old self, the cancer patient.
"I was like 'see you later' and I felt like I was closing a door because every time you shower and you've got nothing there, it's a constant reminder of what you've been through.
"Now I feel like I can get on with my life. It's huge.''
Miss Macnee found a cancerous lump on her left breast three years ago and a few weeks later her breast was removed.
She was promised reconstruction surgery and was told to expect a wait time of about six months.
After the six months lapsed, she was told to expect to wait another year.
After the year passed, she was told to expect the surgery in winter next year.
Since the mastectomy, she stopped swimming with her 7-year-old son Jayden.
After her recovery, she would swim with her son again.
"I can't wait.''
SDHB surgical directorate medical director Stephen Packer said the board had planned to complete the surgery of 42 women on a waiting list for breast reconstruction surgery.
To clear the waiting list, two surgeries were completed by June this year and a further four would be completed by this month.
Another 36 surgeries would be completed by December next year.
The board was working hard to provide more elective surgery and reduce patient waiting times, Mr Packer said.
"As a consequence, the operating theatres and teams are working at capacity and we have therefore contracted extra theatre time in the private sector for this work.''
The plastics service was continuing to plan on how to structure its clinical activity to meet the ongoing need for breast reconstruction, he said.
Miss Macnee said that the board was working to meet the demand was great news.