All very good question KatyCatholic, and you’ve given me a lot to think about. Baptism is the first sacrament that begins our life in Christ, and all Baptisms, having the required form and matter, we accept as valid. So, a person could be baptized without repentance–either through his own fault, or from a lack in his instruction–a then be able to go the confession in order to acknowledge and repent of his past personal sins. The Baptism he received would be efficacious because the form and matter of the sacrament were present.
As to infant Baptism: Infants, and children up to the ‘age of reason,’ don’t sin personally. Without personal sins, repentance is not possible. They do inherit from us, however, the effects of the original sin. From those effects, God saves them. I have wondered how any of us, living in a church of redeemed, having been cleansed of all of our sin by Baptism/Confirmation, could still sin? That’s is a problem as old as Paul’s Letter to the Romans. We do sin, we sin because we sin other Catholics sinning, and to top it off, Catholic children see us sinning and the imitation tragedy continues.
JohnB