As far as I can tell, there weren't any Rigsbys in New Mexico before 1900. The earliest I know them being there is a George who bought land in 1937.
I know of only one Mabel Rigsby born before 1900. She was Mabel Estelle Rigsby born 1893-11-25 in Temple, Bell Co TX, daughter of Thomas Arthur Rigsby + Violet Estelle Hall. Thomas moved around a lot in Texas. He was in Parker Co for the 1900 census, Coleman Co for the 1910, Collin Co for the 1920, and Hardeman Co for the 1930. Mabel is with him up to 1910, and her age is consistent with the 1893 date.
I see her and Clyde on the 1920 census in Eastland Co, which is very close to Coleman Co. Her age is given as 22, the same as her husband's. Either she was lying about her age, or whoever talked to the census taker didn't know.