A community college commencement is, for many, a celebration of second chances.

Consider Su Meck. The 45-year-old homemaker from Gaithersburg graduated Friday from Montgomery College with an associate degree in music. It’s the culmination of a life that, in most senses of the word, began at 22.

In February 1988, a ceiling fan fell on Meck’s head. The blow erased her memory, and she awoke after a week in a coma with the mental capacity of a young child. She no longer knew her husband or her two baby sons. She barely spoke and could not read or write, walk or eat, dress or drive.

“It was Su 2.0,” said Jim Meck, her husband, a systems engineer. “She had rebooted.”

Su Meck had been in her kitchen that evening, making macaroni and cheese. She picked up Patrick, her 6-month-old son, and held him aloft. His body brushed against a ceiling fan and somehow unhooked it. It plummeted and struck Su’s head, according to Jim, the only one in the family with a memory of that day.

An MRI exam showed her brain suffused with cracks, “like shaken Jell-O,” her husband was told. The injury left her with complete retrograde amnesia, the inability to remember the past, a condition sometimes called Hollywood amnesia because it seldom happens outside the movies.

“It was literally like she had died,” Jim said. “Her personality was gone.”

Jim and Su had met five years earlier at Ohio Wesleyan University. He was a junior. She was a freshman. They had left college upon his graduation, married and settled in Fort Worth, where Jim took a job at General Dynamics and they started a family.

A rebellious child from the Main Line suburbs of Philadelphia, Su had removed the “e” from her name to set herself apart from three other Sue Millers at school. She had fallen in with the wrong crowd and done time in juvenile hall. She kept a drum kit in her bedroom.

“I distinctly remember a lot of fighting, a lot of door-slamming and then a lot of really loud drumming,” recalled Mark Miller, her brother.

When Su awoke from the coma, the past was quite literally gone, and she says that almost nothing that happened in the first 22 years of her life has returned. The few flashes of recollection have been brief and mostly fleeting, such as the distinctive feel of a drum tuning key, or the time she sat down at a piano, a few months after the accident, and played “The Entertainer” from what could only have been a memory. She could never do it again.

Friends and loved ones were now strangers. Many found Su’s empty gaze unbearable.

“I remember the first time I walked into the hospital room,” said Barb Griffiths, Su’s eldest sister. “I said ‘Hi, Su, how are you?’ She just looked at me, and there was absolutely no recognition in her face. Oh my gosh, it just tore me apart.”

‘A sort of free fall’

Su left the hospital after two months. She had completed a checklist of tasks, such as riding a bicycle, preparing a meal and reading a simple children’s book. New Su’s first book was Dr. Seuss’s “Hop on Pop.”

She had help — from her husband, other relatives and an au pair. But returning to life as a wife and young mother was “a sort of free fall,” she said.

There was a big hole at the center. Who was she? Why had she married this man, moved to this house, had these children? What thoughts lurked in the mind of the woman who lifted her baby boy from the kitchen floor that fateful day?

“I always wondered: What am I supposed to do now? What is the plan? What is the goal?” she said. “Am I supposed to be this other person who I was, or am I supposed to be this new person?”

To complicate matters, for weeks after the injury Su could not make new memories. She would awaken each day to a house full of strangers.

It would be years before she could remember where she had parked the car at the mall. On the way home, she would circle the neighborhood, clicking the garage door opener for a hint of which address was hers. She became known around the house as the “tidy fairy,” for her habit of putting things away and then forgetting where she had put them.

“We’d have the milk out and we’d put it back in the fridge and close the fridge and . . . where did the milk go?” said Benjamin Meck, 24, the eldest of Su’s three children. Her other son, Patrick, is 23. Kassidy, the only child Su remembers from birth, is 18.

As a toddler, Benjamin developed a prodigious capacity to recall parking spaces.

Talking on the telephone was disorienting in the first few years out of the hospital, so Su and her family communicated with letters. Su wrote hers with the spelling and penmanship of a young child.

“The boys play good with Legos now so givs me a chance to rite,” she told her mother in one mailing. In another: “I hav to go to mor doctors be case fall lots to hitig head bad head ackes.”

Her mother assembled a photo album filled with images of the childhood she no longer knew. “This is your life Su,” she wrote on the first page.

For years, her life as a wife and mother was all Su knew, all she had ever known. She learned her times tables from her children and volunteered at the school library so she could hide in the stacks and read. Benjamin grew up thinking “that school was for both of us.”

Something more

Nineteen years after the accident, in 2007, Su walked into a classroom as if for the first time.

Her children were heading off to college themselves. Su yearned to be known as something other than mother and wife. It was the familiar dilemma of the stay-at-home mom, except that this mom knew nothing else.

“I didn’t really know what I was going to do,” she said. “And Montgomery College was there.”

She asked her children what to bring to class, how to take notes, how to ask questions and write papers.

Her first classes were in sociology, stress management and remedial math — at 42, Su was still multiplying by repeated addition.

Su was a slow learner — her husband can read eight pages to her one. She plodded through assignments, reading difficult passages again and again so she would remember them.

“I think she must have spent hours and hours and hours every day to try to do this,” said Michael Yassa, a brain expert at Johns Hopkins University.

She persevered in the quest for her first college degree, earning a 3.9 average and rising to chapter president of the Phi Theta Kappa honor society.

Here, surely, lay a trace of the old Su, the same stubborn resolve that had driven her youthful rebellion and, later, her obsessive study habits as a teen at Ohio Wesleyan.

“I think that part of her personality stayed with her,” said her sister Barb. “I think she needed to do this for herself.”

Su and her husband are planning a move to Massachusetts, where she will enroll at Smith College in the fall as a transfer student seeking a bachelor’s degree.

Her specialty is still the drums. She plays on a kit her husband bought for her for Christmas four years ago. It sits in the family den, framed by posters of Led Zeppelin, Pink Floyd and the Who. Atop the kit is a small, stuffed Animal, the crazy Muppet drummer, another relic of a forgotten childhood.

Su went through two decades of adult life without telling anyone outside her inner circle that she had no memory of the previous two decades. She didn’t want to be pitied.

The story finally poured out one day last spring at the college, when someone in the honor society asked other members to each bring five things that meant something to them.

Su brought “Hop on Pop.”