The most misleading thing Ancestry does is advertise ethnicity breakdown, unfortunately. We're all here to try to confirm family stories or learn more about our roots. It would be really nice to be able to say "I am x% of this, x% of that" but we can't do it. European DNA is so similar due to migration, trade, etc that we can't cleanly separate pieces into nicely fitting modern day boundaries.

For discussion's sake, let's look at your top 3 regions: Great Britain, Ireland, Western Europe. The latter can and does include German DNA. Okay. Some of your Great Britain and Ireland can be exactly that, but it also may be Anglo-Saxon and Celtic from your German roots. Factor in Italy/Greece perhaps accounting for travels up the Rhine to Roman outposts throughout modern-day Western Germany. You can easily begin to see how the various trace regions COULD play in to what you & your family believe to be true of your roots.

Your family may very well have some Native American...but all this means is that you, generally, did not receive that particular DNA inheritance. That's all. You really can't prove or disprove family lore with DNA at this time.

You're doing the right thing by loading your data into Gedmatch...but be sure you have a strong understanding of just how difficult it can be to definitely claim something. I'm still quite an amateur in this world myself, and it took me some time to wrap my head around the fact that there are not easy answers when it comes to genetic genealogy. Good luck.