You are correct that she would be 46 in 1900. She was born in Missouri, 6 May 1854, but the family lived in Kansas during the Civil War. It is not known (from any of the oral family history) if she was previously married. In her marriage record to Iver Carstensen, she is listed as "Miss".( See attached .) She is the daughter of James W. Smith and Lucinda Thatcher. She is listed in the Kansas City Missouri city directories beginning in 1910. In the 1930 census, her nephew, Charles Milton Smith is living with her. She died in 1933 and is buried in Greenlawn Cemetery in Plattsburg.
I have attached the family group sheet for her and her sibs. I have found her on all census records for Missouri and Kansas except 1900 and 1910.
We are direct descendants of this family.
Hope this answers your questions.