[8] Her final meet of the 2017 season was the Top Gym Tournament where she placed eighth in the all-around and on vault, and she finished fifteenth on the uneven bars.

[17] Her next competition was the City of Jesolo Trophy where the Belgian team won the bronze medal behind Russia and the United States, and she finished nineteenth in the all-around.

[21] Vaelen competed at the inaugural 2019 Junior World Championships alongside Stacy Bertrandt and Noémie Louon, and they finished fifth in the team competition.

[22] Vaelen made her senior debut at the 2020 L'International Gymnix in Montreal where she helped the Belgian team win the silver medal behind the United States.

At the 2021 Osijek Challenge Cup, Vaelen won the bronze medal on the uneven bars behind Nina Derwael and Zsofia Kovacs.

[25] She was selected to represent Belgium at the 2020 Summer Olympics alongside Nina Derwael, Maellyse Brassart, and Jutta Verkest.

Individually, she placed fifth in the all-around, and finished fourth in the vault final behind Zsófia Kovács, Asia D'Amato and Aline Friess with a total score of 13.583.