Janssen wuxuu markii ugu horeysay u ciyaaray xulashada Junior ee Royal Dutch Football Association 17-kii Maarso 2010 kulan saaxiibtinimo oo ka mid ah xulka qaranka U-15 ee England. Sanadkii 2012, waxay kabtan u ahayd kooxda Holland ee U-17 ciyaarihii isreebreebka ee tartanka UEFA Women's Under-17 Championship 2012
Waxa uu sidoo kale hogaamiyay kooxda, kabtan ahaan, oo u soo baxday 2013 UEFA Women's Under-19 Championship. Sanadkii 2014, waxay ku guuleysatay kooxdeeda inay u soo baxdo wareegga ugu dambeeya ee Koobka Haweenka UEFA ee ka hooseeya 19 ee 2014 ee Norway, halkaas oo Nederland ay ku guuleysatay horyaalka markii ugu horreysay iyada oo 1-0 kaga badisay Spain. Janssen wuxuu ciyaaray dhamaan shantii kulan ee tartanka.