Croatian Mary could be Maria, Marija, Mara or Marica
The closest match found may be
Name: Mara Grguric Arrival Date: 18 Oct 1893 Age: 18 Years Estimated Birth Year: abt 1875 Gender: Female Port of Departure: Antwerp, Belgium Ship Name: Switzerland Port of Arrival: Philadelphia, Pennsylvania Destination : Brother Matha GREGROIC at Olyphant PA Last Residence: Furnfkirchen
Are you seeking records in Croatia?If so you need to know exactly where she was born.
Do you have a ship manifest for her?How about Naturalization records?Both of these will likely give her birthplace.
Robert Jerin Croatian Heritage Museum Cleveland Ohio