A mute person can confess. You have sign language for people who are mute. You have pictorial lessons, and many other ways to introduce Christ. All they need to do is nod their heads as a form of confession. Not so with a baby.
What if they can't nod, or what if they have learning a learning disability, or what if they are blind, or don't know sign language?
The point is that you can't make a person's work the thing that saves them, that's works-based salvation. You are placing salvation into human hands and saying it's up to them cross the right t's and dot the right i's--that salvation is something we attain by something we do.
We confess our sins, of course. But it isn't a work of confession that saves us. It is God who saves us by what Christ has done already by His life, death, and resurrection.
Go back and read through Romans 10 again. But read it slowly and carefully. It says if we believe in our heart and confess with our mouth we shall be saved,, but it does not say that confession is what saves us.
What does the Scripture say? Abraham had faith and it was credited to him as righteousness. Faith, not confessing the right things, is what makes us new people--because God gives faith, that is what being a new creation means, having faith. From faith comes confession, from faith comes confessing our sins; from faith comes confessing the truth of God's word, from faith comes the entire Christian life, good works, obedience, etc.
But it is not our works, it is not our obedience, it is not the things we do that save us; it is God alone who saves us by His grace alone, through faith alone, faith which He alone gives.
-CryptoLutheran