I have been told that I don't have a typical German accent and most adults only spot a slight accent after a while or when I tell them that I am German.
With children it's different. I am always astonished how quickly they spot that I may not be English. There have been countless incidents in primary schools, when after my arrival in a new class, somebody asks "Where do you come from, Miss?" On my reply "From Devizes" they say "No, where do you REALLY come from?" So I tell them to guess - and they do: Wales, Scottland, Africa, China, Japan..... they clearly have no idea, but usually somebody gets to the word Germany - until the other day!
A ten year old girl wanted to know where I came from and again I asked her to guess. We happened to stand in front of a world map, so she looked at it for quite a while and finally asked me "Is it from this world?"
I could not think of a reply!