The ministering angels asked the same question when Hagar and the young, wayward Ishmael were wandering in the dessert, and Ishmael was burning with fever and had no water. The angels opposed giving them water, because of all the wicked things that his descendants would do. G-d, however, provided the water, because he judged Ishmael by his actions at that time, which were sufficiently righteous that he didn’t deserve death. The child is a child. As she is right now, she deserves medical care and shelter from the mortar fire.
Children once upon a time were Hitler, Mao, Pol-Pot, Stalin, Bin-Laden, Mohammed... etc. Most of us would have preferred these monsters died while they were still of an innocent age.
Though, I understand your point.