Hi Janell - I am sure there were two Mary Jabaays, since the Jabaay family branched out significantly. It would beneficial to do a search at www.genlias.nl
since you have your Mary's general birthdate. The Dutch spelling is most likely Jabaaij. The website is in Dutch, but there is an option in the genealogy search engine to switch it to English. You can also check with my cousin, Carrie Blocker, who has done extensive research too. Her tree is the Blocker-Robson (or Robson-Blocker) tree on ancestry.
Hopefully this will give you a starting point. Also, have you contacted the local newspaper in Munster for your Mary's obit? It may list her parents there.