2015–2016 In 2015 Petz competed at her first German Junior National Championships where she placed first amongst the AK12 division. During event finals she placed first on uneven bars and balance beam, second on floor exercise behind
Sidney Hayn and fourth on vault. In 2016 she once again competed at the German Junior National Championships where she placed first amongst the other thirteen year olds. Additionally she placed first on vault, second on uneven bars, third on balance beam, and fifth on floor exercise. In December 2016 she competed at the
Voronin Cup where she was partnered with senior national team member
Carina Kröll. They finished second behind the Russian pair of
Lilia Akhaimova and
Elena Eremina. Individually she finished fifth in the all-around, first on vault, fifth on uneven bars, and seventh on balance beam.
2017 In 2017 Petz competed at the German National Team Cup where she placed third in the all-around behind
Tabea Alt and
Pauline Schäfer. In June she competed at the German National Championships where she first in the all-around; during event finals she also won the gold medal on all four apparatuses. The following month she competed in a friendly meet again Italy, Great Britain, Switzerland, and France. She contributed towards Germany's fifth-place finish and placed eighth in the all-around. Petz was later selected to represent Germany at the
2017 European Youth Olympic Festival alongside
Leonie Papke and
Kim Ruoff where she contributed towards Germany's bronze place finish behind Russia and Italy. During the all-around final Petz finished in tenth place after falling on both uneven bars and balance beam. In the event finals Petz won the silver medal on floor exercise behind
Ksenia Klimenko of Russia and placed fourth on vault, eighth on uneven bars, and sixth on balance beam.
2018 In May Petz competed at the German Junior National Championships where she won the gold medal in the all-around and on all four events. In July Petz competed at a friendly competition in
Pieve di Soligo where she helped Germany place fourth and individually she placed tenth in the all-around. In August Petz was selected to represent Germany at the
2018 European Championships alongside
Lisa Zimmermann,
Emma Malewski,
Lara Hinsberger, and
Leonie Papke. Together they finished seventh in the team final. Individually Petz finished fourteenth in the all-around after suffering foot pains. Later in the year Petz decided to forgo competing at the
2018 Youth Olympic Games and instead get surgery on her foot which was causing her pain throughout the year. == Senior gymnastics career ==