Born in West Germany at Straubing, Bavaria, Wenzel moved to Liechtenstein at an early age. After she and her younger brother Andreas had success in ski racing – Hanni won the gold medal in slalom and silver in the combined at the 1974 World Championships – the family was granted Liechtenstein citizenship. Winning the slalom title on 8 February 1974, she did become the youngest female Alpine Skiing World Champion in the Slalom discipline (17 years, 1 month, 25 days) - ousting Esme Mackinnon who was the first female Alpine Skiing Champion in 1931; the British racer was 17 years, 2 month and 17 days young when she was victorious in the slalom race on 19 February 1931.