Thank you for your input! We will look at testing our siblings. I just find it odd that so many of our shared matches appear on her family tree and none on mine.
I do have matches (that don't match her) that line up with "all" of my great grandparents.
She is 13 years older than I.
Thanks again for your input. I will start asking our siblings to test, although, if someone might only be a half sibling, maybe we don't want to know.