This is a good one:
At some stage children are too young to make a credible profession of faith.
Imagine that you are listening in while a father has a conversation with his two-year-old son:
Dad: “Do you love Jesus, Johnny?
Boy: “Da!” (That’s his sound for “yes.”)
Dad: “Do you trust Him with all your heart?”
Boy: “Da!”
Dad: Do you think your sins make you bad?”
Boy: “Da!”
Dad: “Do you give Jesus your whole life?”
Boy: “Da!”
Is it possible that God just saved that boy? Absolutely! Can we have any degree of certainty that this is a genuine conversion? No, we can’t. The age of that child calls into question his ability to understand and respond to the gospel. His cognitive abilities and his self-awareness have not yet developed to the point where we can be certain that he can understand what it is that he is agreeing to. It is not unlikely that the same boy would answer “Yes,” when asked if storks deliver babies and if Santa Claus delivers gifts.
I use this illustration to display what all Christians affirm: There is evidently an age at which a child is too young to make a credible profession of faith. Though that child may be genuinely saved, he lacks the maturity, the autonomy and the ability to count the cost that will give us confidence that his profession is credible. Therefore, it would be unwise of us to baptize him until we can establish the validity of his profession.
https://www.challies.com/articles/when-should-my-children-be-baptized/