Gruy's mother, Julie Elmen, was supportive but initially surprised by the timing of Gruys' project.
"The first thing she said was, That's a great idea, it seems like the perfect experiment for you to do, but you're not going to do it until after the wedding, right?" Gruys recalled.
Elmen told "20/20" that, at first, she was just concerned about her daughter having a "normal wedding."
"I wanted her to be able to enjoy every part of it and be able to look at herself in the mirror and see how lovely she looked on her wedding day."
In the beginning of her mirror-free lifestyle, Gruys admits there were a few maintenance mishaps.
"The first month of the project ...when I was walking out the door...it was maybe a 50-50 shot that I had mascara on my nose."
But quickly, she learned to adapt. Gruys says she trained herself to avoid eye contact with her own image in windows and other reflective surfaces, trusted friends to tell her what looks good instead of relying on the mirror in dressing rooms. And she put complete faith in her hair stylist.
To the surprise of many, Kjerstin says the wedding day was actually one of the easiest days to navigate mirror-free.
"I'm getting my focus back to thinking about the real meaning of the day, which isn't how I look but marrying the love of my life," she said.
Bridesmaids scurried to shield the mirrors from her view. Fittingly, she and Ackermann's first dance was to a song called "I'll Be Your Mirror." The lyrics included "I find it hard to believe you don't know/The beauty that you are."
In March 2012, the experiment came to an end. At an event surrounded by family and friends, Kjerstin Gruys finally looked at her own reflection.
"I had a little ambivalence, and at the same time, pleasure, because I was happy with what I saw," she said.
In attendance was fellow About-Face volunteer Aubrey Toole, who says she hopes people take inspiration from Gruys.
"So many things are important about her message," Toole said. "I think so much of being a female in our society today is seeing yourself from the outside. And her message is really to see yourself from within."
Gruys said she has learned to pay more attention to how she feels, rather than how she looks.
"There is nothing wrong with enjoying, um, looking at yourself in the mirror, ... but it's important for every woman, and man, I think, to really think for a few minutes about whether there is a point of diminishing returns," she said. "Because we have so much more to offer the world than just our looks."