Recently she's added another highlight to her resume: she earned a "highly commended" award in maths in the City Competition.
The competition was led by Professor Marcus du Sautoy and managed by the Technology-Assisted Lifelong Learning unit of the University of Oxford Department for Continuing Education. It encourages participants to reveal mathematics hidden around the city - in buildings, parks, and gardens.
"Professor du Sautoy is known for his work popularising mathematics," Cassandra says. "I read about him and the competition from Plus Magazine. It was a complete surprise for me to be considered highly commended. My parents were overwhelmed when they read the e-mail that I was invited to attend the competition's award event at the University of Oxford."
Cassandra and nine other award-winners were invited to meet Professor du Sautoy in London last Saturday.
Cassandra decided to skip the overseas trip because she had visited Britain just last month. "I really want to ask Professor du Sautoy about his work. I have made a video, introducing myself and asking him a few questions. He has promised to respond by sending me a video clip," Cassandra says.
The competition was launched in April when Cassandra was busy with her A-Level exams. She had to wait until after April 18, when she completed her exams, to begin working on her project. That left her only two weeks until the deadline.
"It is easy to identify mathematics in structures in Hong Kong," Cassandra says. "I listed six buildings: The Hong Kong Space Museum, Peak Tower, Bank of China Tower, the airport, Hong Kong Convention and Exhibition Centre, and the Hong Kong Cultural Centre. I wanted to talk about them in terms of mathematics. In the end, I chose to go only with the Space Museum because of the time limit."
The building is shaped like an egg and Cassandra's project investigated the properties of egg-shaped structures and their relationship to mathematical equations.
Cassandra hopes to have a career in cryptology. "It is a subject that combines mathematics and computer science, both of which interest me. My first two choices for university are mathematics. My third choice is English because I enjoy reading and writing."
Cassandra has an abiding curiosity about the world. "I listen to the news every day, and I read both Chinese and English newspapers. I like to explore different issues," she says.
"She has unique ideas," Ip Choi-wan, Cassandra's teacher, says. "She was a member of our debating team that participated in the Nesta-SCMP Debating Competition. Her outstanding arguments and swift thinking helped her classmates a lot."
With an IQ of 135, Cassandra was always considered gifted. But she shrugs off the label. "My teacher has asked me to attend some courses for gifted people but I turned it down. I believe in The Bible and that everyone is equal, so it is pointless to say that somebody is better," she says.