Possible she isn’t from same family
Ancestry.com. U.S., Find A Grave Index, 1600s-Current [database on-line]. Provo, UT, USA: Ancestry.com Operations, Inc., 2012.
According to "The Descendants of Thomas Whittier", she was the daughter of Porter Whittier and Lois Piper. See https://babel.hathitrust.org/cgi/pt?id=wu.89062438676&view=1up&seq=125&q1=1292