Today is the 90th anniversary of her death.
There are a number of child saints, but most of them are martyrs. Until the pontificate of St. Pius X, children had been considered incapable of heroic virtue. Bl. Jacinta and her brother, Bl. Francisco, may (if I am not mistaken) be the first children to be raised to the altar on the basis of heroic virtue since Ven. Pius XII canonized St. Dominic Savio in 1954.