There are a number of people with the birth name Fiona Jacobowitz online. However, I would need more information to determine which Fiona Jacobowitz you are interested in.
Her full name: Princess Fiona Fiona O_O
Fiona Cheeks's birth name is Larissa Kelley.
Fiona Wood's full name is Fiona Melanie Wood.
Fiona Apple's birth name is Fiona Apple Maggart.
Fiona Musson's birth name is Fiona Anne Musson.
Fiona Shaw's birth name is Fiona Mary Wilson.
Fiona Stanley's birth name is Fiona Juliet Stanley.
Fiona Crossley's birth name is Fiona Mary Crossley.
Fiona Lewis's birth name is Fiona Marie Lewis.
Fiona Ferrer's birth name is Fiona Ferrer Leoni.
Fiona Dolman's birth name is Dolman, Fiona Jane.
Fiona Gubelmann's birth name is Fiona Victoria Gubelmann.