When she turned 108, she was named one of Montana's two oldest people.
And when Self turned 109 a few weeks ago, she got a whopping birthday discount based on her age: A restaurant gave her a 109 percent discount on her meal - meaning the restaurant actually paid her to eat there.
Restaurant owner Nick Alonzo was there to hand her the dollar and change, and in return she gave him a kiss on the cheek.
"I'll come back next year," Self said, according to her daughter Shirley Gunter, 86. "Don't tell his wife I kissed him."
The Montana Club's birthday discount is legendary in Missoula. It's a popular steak and seafood restaurant, and, most evenings, a customer or two can be seen collecting the famed discount: 1 percent off a meal for each year of a person's life.
Self started going to the Montana Club for her birthday when she was 99. The following year, she got a 100 percent discount.
At the time, Alonzo laughed with her and told her: "Next year, I'm going to have to start paying you."
Every year since then, that's exactly what has happened.
So when Self turned 109 on Aug. 17, there was no question about where she'd go. She sat down at a table near the window with about 20 members of her family, ready to eat.
She ordered the breaded shrimp platter for $14.99, which came with a salad, a loaded baked potato and coleslaw. Alonzo showed up at the end of the meal, saying he wouldn't miss her birthday.
"I'm always there," Alonzo said. "Somebody has to pay her."
Last year on her birthday, Alonzo suggested that she take the money he gave her and go play the slot machines in the back of the restaurant.
She told him, "Nick Alonzo, I am not leaving my money here, I'm taking it home," according to her daughter.
This year, he made the same suggestion and she quipped back, "If I could get there, I would."
Self, who has been a widow for 18 years, had two children, but one of them died before she turned 100. She has seven grandchildren, six great-grandchildren and four great-great grandchildren, with another expected this month.
Her daughter said Self weighs 110 pounds, as she always has, and is in excellent health except for some hearing loss. She uses a wheelchair occasionally but refuses a cane, and when she walks, she "holds onto whoever is next to her."
Gunter said that her mother doesn't take any medicine, and that her doctor says, "She only comes in here once a year to let me know she's alive."
In a phone call with The Washington Post, Self said she attributes her longevity to not overeating and to her laid-back approach to life.
"Take life as it comes and don't get too excited about anything," she said.
Her daughter added: "She always said, 'This, too, shall pass. If you're upset, just get down and scrub the floor.' "
Self isn't scrubbing the floor anymore, but her daughter said she still enjoys plenty of activities, such as going camping with her granddaughter.
"She sleeps in the camper," Gunter said. "She loves it."