The hardest thing is starting.

Kathleen Mattison should know: It took her 40 years to get the time and gumption to finally become a dentist.

“I had a coffee cup that said, ‘What would you do if you could not fail?’ I’d look at that cup every day,” the 60-year-old Forest Lake native says. “You can think about it and think about it and think about it. But you have to just start.”

University of Minnesota officials say the Harley-riding mother of three is the oldest to receive a doctorate of dental surgery in modern memory.

“My biggest challenge was all the technology, but I had very helpful classmates,” Mattison says. “They would help me with the technology, and I would patch or mend their scrubs. It worked out.”

She convinced her husband to mortgage their home — and admits she likely won’t get the money back. Mattison’s goal is to ride her Harley Low Rider across rural Minnesota, helping community clinics in need.

“There’s so many places that need dentists right now. I’ll work as long as my health holds out. My health, my hands, my back, my neck, etcetera.”

BIGGEST CHALLENGE: REJECTION

A lot of people would keep a little distance from the dentist after an experience with braces, but not Mattison.

“It interested me after getting braces. The ability to move things around in there. But it was pretty unusual for a woman to become a dentist back then.”

Instead, at age 18 she went to the University of Minnesota’s dental school to become a hygienist, graduated two years later in 1975 and started at a practice on St. Paul’s greater East Side.

“She was always reading dental (publications), had a very keen interest and inquisitive mind,” said Dr. Bob Hobday, Mattison’s employer for the next 37 years. “Her mind was always running way beyond hygiene.”

After 10 years, Hobday told her: “You need to be doing more than you’re doing.” It would be something he’d repeat for decades to come.

After Mattison’s mother died in 2004, she considered it a little more. She walked into the university’s transcripts department and was told they’d have to dig through microfiche files.

“Normally it’s a couple days; not for me,” she said.

Then came the bad news: she’d have to retake most of her classes. The science classes, in particular, were long past their expiration date.

Over the next several years, while still working as a hygienist, she started a new mantra: “One class at a time. Just keep going.” And there was always her coffee cup to help her along.

After five years, Mattison completed her courses and applied to the University of Minnesota’s School of Dentistry. After getting rejected the first time, she admits feeling dejected.

“I guess I didn’t think it was going to happen,” she said.

“She thought that might be unreachable at her age,” Hobday remembers. “She was really bummed, because she was working so hard for it for so long.”

Hobday told her to apply again. “They probably rejected you because they don’t think you’re serious. Do it again, and they’ll know.”

Also, Hobday had made plans to sell his practice and move to Wisconsin. One day in 2011, Hobday tentatively informed her that a sale had been made.

“I got my acceptance letter that same day,” Mattison says.

IT TAKES COMPASSION. AND CONVINCING

Naty Lopez, the admissions official who interviewed Mattison for the dental school the second time around, remembers telling her: “You will be in class with young ones, energetic.”

She remembers Mattison’s reply equally well: “She said this was her life’s dream, and it had been delayed so many times.”

When Mattison applied, Lopez says the school had already moved beyond looking at just grades and test scores. Those juggling studying time with other responsibilities — such as a full-time job or taking care of family — would actually get extra consideration. “It’s easier to get good grades if you’re not working.”

Over two years, Lopez helped conduct a two-year study of previous applicant pools and calculated a rubric to give such “nontraditional” applicants a couple bonus points on their application.

In the medical fields in particular, Lopez says, admissions officials are looking for applicants who have demonstrated compassion — and life experiences help.

For Mattison, “She said, ‘I’m not doing this for myself.’ She wanted to fulfill her dream of doing something for others. That told us she was a compassionate individual, putting others ahead of her, which we look for in the dental industry.”

Plus, she had something Lopez called “the persistence to pursue.”

“Some people would have said, ‘Oh well, it didn’t work, I give it up.’ But not her.”

THIS RIDE ISN’T OVER

Some time after Mattison was accepted, her daughter called her.

“Mom, where are you?” the daughter asked, wondering about all the noise in the background.

Mattison had just joined a dental fraternity and was on a downtown party bus with a beer in her hand.

“On a party bus. It’s initiation.”

“No, really, Mom, where are you?”

Reflecting on what it was like to go to school with classmates the same age as her children, Mattison says, “It made me miss my own kids less.”

Several years later, Mattison did a weeklong internship at Scenic Rivers Dental Clinic in Cook, Minn. — a rural community clinic about an hour south of the Canadian border.

“I got an email from her. She said, ‘I’ll get up there when I can, depends on the weather, I’m riding my bike,’ ” remembers Dr. Tim Sprouls, one of the dentists there. “I thought: ‘Your bike?’ ”

When Mattison arrived, she spent a lot of time talking to the human resources guy, a fellow Harley rider.

“I had no idea what they were talking about,” Sprouls said. But Sprouls had some idea about Mattison’s patient rapport.

“The patients were asking her to come back. She was an excellent clinician, too. Her diagnosis was good; her hand skills were excellent.”

Recently, Sprouls asked Mattison the same thing his patients did: Will you come back?

On Friday, Mattison received a 30-second ovation in the U’s Northrop Auditorium — the same auditorium she sat in for her hygiene degree — when she took the stage to receive her diploma. Out of 108 graduates, she was one of two to receive a leadership award from the Academy of General Dentistry and one of four to receive an award for clinical work by the Academy of Operative Dentistry.

Later her husband posed for a picture with his empty pockets turned inside out. Still, Mattison says, she’ll take Sprouls up on his offer.

“That’s why I went back to school. … We’re trying to get more dentists up there, anywhere up there; a lot of those rural areas really need dentists.

“So I’ll ride up there, move in with my coffee pot and my scrubs, and just start working.”

Tad Vezner can be reached at 651-228-5461 or follow him @SPnoir.