that asn't my point - only born is different than first bornFirstborn was a title given AT BIRTH, not after subsequent maternities. (See Exodus 13:1-2) The “firstborn” were not given the title because there was a “second-born.” Rather, it is a title given at birth. Being the firstborn does not require subsequent siblings nor does it imply there are or will even be subsequent siblings.
first born means the first - only begotten means there will never be others
so if mary was to never have any others the term only begotten would have been used - not firstborn