If you want to know for certain then I would suggest a DNA test (unfortunately it costs). I submitted my DNA for testing as part of the IOM family history project (run by John Creer).
This showed that I was directly related to another IOM Casement.
The only problem could be that you are female, the project only involves males. And the famly name has to be one of the twenty most common in IOM history.
The test showed that my HAPLOGROUP was I1 which points towards Viking (Scandinavian) ancestory.
But HAPLOGROUP isn't dependent on the IOM project, you could still have it done anyway.
By the way, physically, I'm bald (what's left is grey/mousey brown), my eyes are muddy brown and I'm six feet tall! So fairly watered down!