How and when did Mary get to Australia?

I AM a descendant of an Irish ancestor, Mary Kelter, who married William Field in Geelong — then Port Philip — in Australia in 1841. On her death certificate, Mary Kelter’s father was noted as James Kelter, hotelkeeper.

Mother Mary Kelter (surname unknown). A family bible notes that Mary Kelter was born in Cork, but her death certificate notes she was born in Waterford, circa 1824.

I cannot find any records of Mary or James Kelter prior to this date where she came from, how or when she travelled to Australia, our family history in Ireland.