A religion Question about heaven and hell?

Ok so Lets say that there was a child born and if that child died like a month later but he didnt do anything bad would he go to hell or heaven?? but if that child lived and grew up he would become like the next hitler how does that proses work?? Its like if he grew he would be bad and go to hell but if he died young and never got the chance to do anything bad would he go to heaven??