"I mustered the courage to join the choral speaking group," says the 16-year-old Form Four student at Delia Memorial School in Kwun Tong. "But I didn't do well. I got stage-fright and forgot my lines,"
She was disheartened both by her poor performance and by her mother's comments about it.
"She said I wouldn't do any better even if I tried, so I should just concentrate on my studies," Mary recalls.
But she persisted. In Form Three, she joined a drama club and soon made her stage debut, winning praise from classmates and friends.
"Dignity comes from believing in yourself, even when others don't believe in you," Mary says.
That's the message she shared with 250 students at a Global Dignity Day in her school last week.
The students started off with a group discussion about what dignity mean to them before they gathered in the hall to listen to stories like Mary's.
Global Dignity Day, which will be officially celebrated October 16 this year, was launched in 2008 by three young global leaders at the World Economic Forum.
The event is now celebrated at schools in 50 countries worldwide.
Diana Tsui heads the Hong Kong part of the movement, in which seven schools have so far taken part.
"This is a platform for students to learn about dignity by sharing their experiences with each other," says Tsui, who was a Young Global Leader in 2011, and is now head of corporate social responsibility and diversity of KPMG China.
Connie Lau Man-yuen, head of the school's multicultural education events, agrees. "Dignity is a topic we value in our school with our diverse mix of students from 25 nationalities and cultures," she says.
"Through the event, we hope students will build their understanding of their identity and worth, and learn to respect others."
Back in the school hall, more students come forward to share their stories of how they have learned to face the challenges in their lives.
Vicky Cheng Tim, a mainlander from Guangdong province, is one of them. "When I first arrived two years ago, my English was poor and no schools wanted to accept my applications," says the 16-year-old. "I was very hurt; I felt rejected."
To "regain her dignity", she has spent the last two years studying very hard.
"I read a lot of children's literature in English and I looked up every word I didn't understand. When people took away my dignity by judging me, I needed to take it back," she says.
Stories like hers touched fellow student Rajinder Deol, 16. "It was very inspiring to listen to all these stories which offer us a positive view of life," he says.
"When you know what your classmates have been through and how they've tackled their problems, it makes you want to do your best, too. Every school should have a Global Dignity Day," he adds.