Kammala jumla mai zuwa: Peno ya kasance memba na matasa 'yan wasa na Serbia. Tare da 'yan wasan matasa na kasar Serbia, ya taka leda a wasannin da suka biyo baya: 2012 FIBA Turai Under-16 Championship, inda ya lashe lambar tagulla, 2013 FIBA Turai Under-16 Championship, inda ya lashe lambar azurfa kuma an zabe shi zuwa All-Tournament Team kuma an kira shi MVP, 2014 FIBA Turai Under-18 Championship, inda ya lashe lambar azurfa, 2014 FIBA Under-17 World Championship, inda ya lashe lambar tagulla,
2015 FIBA Under-19 Gasar Duniya, da kuma 2016 FIBA Turai Under-20 Championship.