The family sailed to America in 1856 on the ship Thornton, and Mary Ann is listed as a "Spinster" on the ship manifest.
There is a major discrepancy concerning her birth date. Her birth information that we have located is as follows:
* FamilySearch: 12 February 1832
* Utah State History Cemeteries & Burials Database: 19 January 1838
* Mary Ann's obituary: 17 January 1830
* A history of her in FamilySearch says that some church records where she is listed with her parents: 17 January 1832.
The bottom line is that further research is needed to determine her actual date of birth.