Athen(i)a is a digital ghost before that 1806 marriage.
I wish I could be of more help, but I will mention that Mansfield was a part of Norton until 1775, meaning that if Athena was a lifelong resident of Mansfield before her marriage, then she would have been born in Norton.
I've looked through these names of Wetherell/Witherell (and all the various spellings) in Norton trying to hypothesize if any of the names are close matches to Athen(i)a.
(Vital Records of Norton, MA)
https://hdl.handle.net/2027/coo1.ark:/13960/t70v91j29?urlappend=%3Bseq=151
VERY interesting to me is the repeating of the name "Zaphaniah" Wetherell. However, the DOBs are decades earlier than 1782. Frustratingly, the only Wetherell girl births in Norton between 1781-1783 are girls named Zilphe and Rachel.
The other options are to leaf through these Norton town records:
https://www.familysearch.org/ark:/61903/3:1:3QS7-L979-7P2R?wc=Q4D4-ZJS%3A353350701%2C353561401%2C353561501&cc=2061550
This book was likely one of the books extracted to make the Norton Vital Records linked above, meaning it may not contain new information, but maybe there is an Athenia/Zaphania mentioned circa 1782?
OR
Visit an LDS FamilySearch center near you and examine these church records.
https://www.familysearch.org/search/catalog/387882?availability=Family%20History%20Library
Again, these records were likely extracted to create the vital records volume, but comparing the texts could reveal mistranscriptions and alternate spellings.