If you were to redo tests through ancestry, you would likely get the same answer. 23andMe actually does a better job at determining your haplogroup as far back as possible. You can almost be sure that your German ancestors came from Ireland before they lived in Germany. The 1700s is near history. The haplogroup you belong to goes back to 300 AD and provides an ancient picture of your ancestry. You belong to a specific haplogroup which is actually very interesting because it is suspected to have a large number of descendants from the legendary King of Ireland, Niall of the Nine Hostages. It's a very interesting haplogroup.