Tetzlaff was born in 2000 in Lower Hutt.[2] She gave up gymnastics as an 11-year-old,[3] in part because of the drive to push on through injuries. She tried circus performance[4] but eventually settled on climbing, a shared interest with her younger brother.[3] By age 13 she was competing in speed, but her fear of heights sometimes left her frozen at the top of the wall for many minutes.[5] While finishing at Wellington Girls' College, at age 17, she went to Germany for an exchange month.
For years Tetzlaff had to train in other countries, as the nearest speed wall to New Zealand was thousands of km away in New Caledonia.[3] In 2018 she moved from Wellington to Tauranga,[3] where she uses a speed wall in Blake Park at Mount Maunganui.[5]
Competition climbing
Tetzlaff entered the 2017 Oceania Youth Championship in Nouméa, signed up for the qualification event for the 2018 Summer Youth Olympics "on a whim",[4] and medalled in all three of speed, boulder, and lead, taking gold in speed and boulder.[6] That result took her to the Youth Olympics in Buenos Aires, Argentina, where she took 21st place in sport climbing at the 2018 Summer Youth Olympics, a combined event featuring all three disciplines.[3]
Even before the 2018 Youth Olympics, she stated: "my sights are set on the 2024 Paris Olympics".[4] When she won the Oceania qualifier in 2023, she and teammate Julian David became the first two New Zealanders to gain a place in the 2024 Olympics, and they will be the first New Zealanders to compete in climbing at the Olympics.[7] Her time in the final qualifying race, 8.54 seconds, was a personal best but well behind the times of the top contenders at the Olympics.[3] Her goal is to continue improving her times to reach the world standard by 2028 and 2032.[5]
In a world cup in Chamonix prior to the Olympics, she set another personal best and an Oceania record with a time of 8.40.[6]