Autosomal DNA Match

I have received notification of a very distant autosomal DNA match with a 6th great granddaughter of Henry the Immigrant. I am a 6th great grandson of Henry. She is descended from James, son of Henry the Immigrant. I am descended from Edney son of Henry the Immigrant. It is surprising that we show a match, albeit small, since she and I are 7th cousins. Usually autosomal testing will not show matches over this distance.