You describe a moral analysis using situation ethics criterion. Situation ethics has been condemned as unacceptable by the Catholic Church when placed in opposition to the moral law.

The Church ban on abortion does not hinge on whether or not the fetus is a "person", which is a legal term, or murder. While some do not consider abortion a sin, a Catholic is bound to do so.

As a Catholic I feel completely comfortable opposing your position with my votes and presenting reasons why your analysis is morally deficient.