 Pari gbolohun yii: Terzić ṣe ipa akọkọ rẹ ni ere idaraya ipele agbalagba ni akoko 2012. O gba ami ayo fadaka ni 2012 World Junior Championships ni Athletics pẹlu akoko igbasilẹ orilẹ-ede Serbia ti 4:07.59 iṣẹju fun 15000 m. Ní ọsẹ kan lẹyìn náà, ó gba ẹyẹ 1500 m àti 3000 m ní Balkan Athletics Championships. O gba ipo kẹrin ninu 1500 ni Ipade Rieti ati ṣiṣe igbasilẹ orilẹ-ede miiran ni ijinna 1000 m ti kii ṣe deede ni ipade Athletics Bridge. Ni ifarahan ikẹhin rẹ ni ẹka ọdọ, o gba ami ẹyẹ goolu ni : 2012 European Cross Country Championships. Àwọn ojúewé wọnyí jápọ mọ O ṣe ayẹyẹ Ọdun Tuntun nipa bori ni Silvesterlauf Peuerbach 5K ọna ọna, ti o lu oludije marathon ti o ga julọ Irina Mikitenko. 