We’re talking here about baptism as you believe it to be, salvific. A parent doesn’t make a decision for a child as to whether or not they are saved. Baptism/Dedication, fine, but neither is salvific. Only YOU, as a person, can decide whether or not you want Christ.
That is obviously true, but we don't think a mere desire for Christ is salvific alone anyway. I understand that in Protestant theory of "faith alone" child baptism makes no sense because a child cannot make informed decisions. But the Catholics think differently. Baptism is salvific because sovereign all-powerful Christ makes it so; the will is only necessary so that no forced conversion may happen. It is true that we do not rush to baptize a child because we trust the loving God to save even the unbaptized in case of a sudden death. Neither do we delay baptism, like early Christians sometimes did, so that more sin is washed off when it finally happens. But we baptize children reasonably promptly. The short saying is, it is not important at baptism that the child knows Christ; it is important that Christ knows him.
Note that it is consistent with the "Let the children come to Me" episode where Christ taught that the innocent, simple mind of a child is no obstacle to a union with Him.