Sjöberg played in the World Junior Curling Championships in 2014, 2015, 2017 and 2018 as a member of Team Isabella Wranå. In 2014, her team of Isabella Wranå, Jennie Wåhlin, Elin Lövstrand and Almida de Val had a fourth-place finish, after they lost in the bronze medal game to Russia. In 2015, she and teammates Wranå, Wåhlin, Johanna Heldin and Johanna Höglund again finished fourth after this time losing to Switzerland in the bronze medal game. She was back at the event in 2017 where her team won the gold medal, defeating Scotland's Sophie Jackson in the final, and lost just two round robin games in the process. The next year the same team went undefeated in the round robin, but ended up losing to Canada's Kaitlyn Jones in the final. This team also represented Sweden at the 2017 Winter Universiade, where they took home the bronze medal. Sjöberg represented Sweden one more time at the juniors in 2019 as alternate for Tova Sundberg. They placed sixth.