Baptism and Cohabitation?

A young couple requested the baptism of their child. I therefore saw them with a deaconess. There was just one awkward aspect of it: they were unmarried. We said that we were pleased that they wanted to take baptismal vows -- and laid before them two possibilities. The first was to “set their lives right”, and from this foundation then to take their baptismal vows. We outlined possibilities for them to get married, and said that we would cover the costs. Alternatively, we suggested an old Reformation idea: godparents were God-fearing people who were appointed as “spiritual guardians” where the parents were not competent to take the vows. Eventually we decided on the second option -- and the baptism itself was a glad occasion. OBSERVATION: The mother was very young. Our deaconess kept calling her “my kind” (my child).