How can I belt without injuring my voice? (Good Day- IU)?

I CAN belt pretty well...that is if I don't care about the state of my vocal cords and just belt. Right now, I'm singing a korean song called "Good Day" by IU,and she has this one part where she goes really high/ belts (the "three octave note"). I can do that, however, I can't sing it more than 2 times in a row because then my throat becomes so sore. But then again, when I sing songs like Hero by Mariah Carey, I don't seem to have as big of an issue. So, what I want to know is--am I belting in the wrong way, or are those notes just high and not meant for singing for long periods of time? I'm 16, so I really don't want to damage my vocal cords at this age. Thanks!