Koppang started playing handball in Vadstena HF. She also played football in Vadstena GIF. In 2018 she moved from Vadstena to attend a sports school, and with that she changed to IK Sävehof's youth team. She also continued playing football, now for Göteborg FC's youth team, however only for around 6 months until she decided to quit football and fully focus on handball.[2] The season of 2020/21 was her first in IK Sävehof's senior team.[3]
When she was 16 she played for the Swedish U16 national team in football.[4] In handball, she participated in the U17 European Championship 2019, where Sweden brought home a silver medal.[5] She also participated in the U19 European Championship 2021, where Sweden ended up on the fourth place. There, she was chosen for the All-Star Team as best right back.[6] She made a debut in the senior national team in April 2021 in a game against Hungary, when Sweden's original squad had a Coronavirus outbreak and had to be fully replaced.[7]
