No devout Catholic in 1973 or any other year would ever have even CONSIDERED the alternative.
Yes. Most would have given up the baby for adoption OR given the baby to a black family to raise.
Someone who is "devout" is nonetheless capable of sin. We are weak creatures; it is one thing to say you will do the right thing and another to actually do it if and when it is required, especially if the consequences mean social isolation or rejection by family.
Sadly, when such a situation arises, many people give in to their prejudices, fears, or pride and ignore what they learned in church. She should be asking for forgiveness for what she did to her child, not trying to justify her actions.