Praise be to Allah, the Lord of the World; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions.
Generally speaking, there is a long discussion among scholars concerning "Hisab" of non-Muslim children (who are not pubescent). But, according to the most preponderant opinion, no one knows the fate, i.e. if they will enter Paradise/Hell, of such persons in the Hereafter except Allah, The Great and Almighty, since He alone knows their deeds, good or bad.
In this vein, the Prophet (Sallallahu Alaihi wa Sallam) said: "Only Allah Knows what would their deeds be, i.e. good or bad" . [Reported by Imams Bukhari and Muslim ].
Allah knows best.