You are confusing the two people named Ole Gundersen.

John Gundersen Skjeggestad (°1833) is the son of Gunder Olsen and Berthe Johnsdatter. John's brother, Ole Gundersen Skjeggestad (°1826) took over the farm Skjeggestad and did not come to America.

The other Ole Gundersen is the one that married Martine. He was originally Ole Olsen Skjeggestad (°1870), but changed his name to Ole Gundersen when he arrived in America in 1892. His parents were Ole Gundersen and Kari Eriksdatter.

Your family is indeed confusing with all the people named Ole and Gunder!