At the 2021 Osijek Challenge Cup, Vaelen won the bronze medal on the uneven bars behind Nina Derwael and Zsofia Kovacs. She was selected to represent Belgium at the 2020 Summer Olympics alongside Nina Derwael, Maellyse Brassart, and Jutta Verkest. She competed on the vault, uneven bars, and floor exercise in the team final where the team finished eighth.