Of course there were the terrible times: The angry outbursts. The ache of loss. The undeniable sorrow.

In the last three years of her life with Alzheimer’s disease, Nicole MacLean’s mother, Sally Horrocks, sometimes forgot who her daughter was. A gentle woman all her life, Horrocks would strike out violently at MacLean in confusion and fear.

But there were days to cherish, too, especially when mother and daughter took part in the Philadelphia Walk to End Alzheimer’s together.

“I had her in a wheelchair and I pushed her through the walk, and she thought this gathering was all for her. I let her believe it because it made her happy,” recalled MacLean, 63, of Havertown. “People would come up to her, touch her, talk to her, and hold her hand. She just felt so incredibly special.”

In July 2019, when Horrocks was 81, Alzheimer’s took her life. MacLean vowed to continue participating in the annual walk in her mother’s honor.

So this Saturday at the annual event, MacLean will do just that. But for the first time, she will also walk for herself.

In August, she was diagnosed with early-onset Alzheimer’s.

The first chilling sign of the disease had come just months after her mother died.

“I had gone to the grocery store, and then the next thing I remember, I had driven to a town, and I didn’t know where I was,” she said. “I didn’t know how to get home. I didn’t know how I had gotten there, but I was the only one in my car, so I had to have driven there.”

Her doctor dismissed her fears, saying she was “too young” for Alzheimer’s. But the memory lapses continued. Finally, early this year she went back to her doctor. Mild cognitive impairment, she was told. She didn’t buy it. So when she heard about an Alzheimer’s assessment through a pharmaceutical clinical trial, she signed up.

She was at work when she got her diagnosis in August.

“I cried,” she said. “I thought I was prepared, but actually hearing the words, I cried.”

A coworker comforted her as MacLean let the news sink in. And when the initial shock subsided, so did her tears.

“I was like, ‘OK, thank you, God — now that I know, I can be prepared.’ I thought of it as a gift because I can make plans now. A lot of people who don’t get that early diagnosis don’t know to make plans. Then it becomes too late.”

At Saturday’s opening ceremony at Citizens Bank Park for what has become one of the nation’s largest Alzheimer’s walks, MacLean will be present in the event’s Promise Garden to lift a blue flower, a gesture representing and honoring the more than six million Americans living with this disease. (Caregivers will carry yellow flowers. Purple flowers are for those who have lost a loved one. Orange flowers are for advocates.)

MacLean, who took part in the national fund- and awareness-raising event long before her mother was ever stricken, was chosen for the flower-raising honor by the Philadelphia-area walk organizers in part because of the singularly graceful way she has faced her diagnosis.

“Nicole’s just a light,” said Samatha Sayward, senior walk director. “I lost my grandmother to dementia; I’ve seen firsthand the devastating impact it has on families and what it does to the person who has been diagnosed. I felt Nicole could bring a positivity [to the walk] that people with Alzheimer’s and their families could really use.”

MacLean’s gracious bearing is all the more remarkable because she knows exactly what awaits her. In the three years her mother shared MacLean’s home after the 2016 death of MacLean’s father — Horrocks’ caregiver in the earlier stages of the incurable brain disease — MacLean gained intimate knowledge of what Alzheimer’s does to a person.

Before her mother, a former bookkeeper, moved in, MacLean imagined all the things they would do together — day trips to craft shows, Longwood Gardens, and the zoo; road trips to places like the Florida Keys and Mount Rushmore.

But reality quickly displaced her fantasies.

“There were days my mother didn’t know where she was or who I was. She didn’t know where my dad was,” MacLean said. “I realized her Alzheimer’s was more advanced than I’d thought.”

And, increasingly, her mom could not remember doing certain things, even if there was physical proof that she had.

Other people’s reactions to her mother’s cognitive decline were dispiriting.

“People would ask me, ‘How’s your mom doing?’ — and she was sitting right next to me. That was very sad,” said MacLean.

That’s why it was so special for Horrocks to attend MacLean’s church, a home-based congregation where people were accepting and kind to her. Sometimes, singing a hymn from the past or invoking a memory from long ago could bring her back, remind her of who she was.

But as the disease advanced, Horrocks began to “disappear into an unknown world where she was no longer my mom,” says MacLean. “It was almost more than I could bear.”

Toward the end of her life, Horrocks would sometimes erupt into rages.

“There were angry words, temper tantrums, and throwing things. My mom actually would be violent with me,” said MacLean. “I can’t tell you how many times I’d sit in my car and cry. It was a blessing she didn’t remember from one day to the next because it would break her heart if she knew the way she treated me.”

MacLean now believes fear — deep, wordless — drove much of her mother’s behavior.

“Some days I would look at my mom, and she would have a look on her face that showed she was scared to death,” said MacLean. “She knew something was happening, and she was terrified.”

As for her own immediate plans, MacLean, a single woman with a busy, full life, wants to spend as much time as she can with loved ones; she has family — a daughter, her daughter’s husband, and two grandchildren — as well as dear friends.

“I’m a little sad that I may start to forget people,” she said. “But before that starts to happen, I’m going to make sure I fill every moment and every second with them with as much love and joy as I can while I remember it.”

She wants to volunteer more, too, doing things like taking puppies into a nursing home “and watch people’s faces light up.” An older woman in her church has been to every state but North Dakota; so next spring, MacLean plans to accompany her there.

“I very much have a servant’s heart, and when I am helping other people, that blesses me more than it blesses them,” she said.

And she would like to start a support group for Alzheimer’s caregivers to share what she has learned so “they understand they’re not alone, and it’s OK to be frustrated, it’s OK to be mad.”

She would urge them to make time for themselves, she said, and to never take personally the hurtful things their loved ones with Alzheimer’s may do or say.

“It’s the disease that’s talking,” she said. “Just remember — they’re hidden someplace inside.”

MacLean, who is a branch officer adminstrator with Edward Jones, the financial services company, said she hopes many good times lie ahead for her. She has a five-year plan that includes retirement and a 10-year plan that could encompass new medical breakthroughs. Nonetheless, she has already arranged for a couple from her church to care for her when she can no longer live alone. They have her power of attorney, and she said her retirement savings should keep her from becoming a financial burden on anyone.

As her disease advances, she has told everyone, she wants them to remember, “I’m still me. Still talk to me. Still hug me. Still hold my hand.”

Since her diagnosis, she said, she has experienced more of what she calls “time hiccups.”

“Just recently, I lost a span of 10 minutes; I don’t remember anything that happened in that time,” she said. “People who were with me say: ‘Well, you were talking to us. Don’t you remember having this conversation?’ And I don’t remember it at all. It’s scary. It reminds me, ‘This must have been what it was like for my mom.’”

And that brings MacLean to another way to use the “gift” of her early diagnosis: as an activist.

Just as Michael J. Fox, the actor, called attention to Parkinson’s disease with his own health battle, MacLean would like to use her experiences to lobby for greater Alzheimer’s research funding and support.

“We have talented scientists out there. I know they can find a cure for this, but it takes money,” MacLean said. “Before I get too advanced, I want to be an advocate so people higher up can hear advice from somebody who’s been there and is there now.

“I can’t imagine I’ll ever be a Michael J. Fox, but I can be a Nicole MacLean,” she said. “Maybe people will say: ‘Nicole MacLean. Isn’t she the one fighting for us to find a cure for Alzheimer’s?’

“You never know what God has planned.”

For more information about the Philadelphia Walk to End Alzheimer’s, visit act.alz.org/Philadelphia.

The Alzheimer’s Association Delaware Valley Chapter is available with resources, support and information 24 hours a day, 7 days a week at alz.org/delval, or through the Alzheimer’s Association 24/7 Helpline at 800-272-3900.