Teaching 40 Javanese kids

I was asked to visit (and teach) in a Junior High in Wonosobo, Java. For most of the students, it would be the first time to have 'a native English speaker' in the classroom. When I tried to explain to the team of teachers that my mothertongue is Dutch, and that I am far from a native speaker, they just shook their heads in disbelief: 'To us, you are a native speaker. First of all, you are blond, you have white skin, blue eyes and a pointy nose. On top of that, your English sounds a lot better than all of us teachers together. And not to forget your country of origin: it's somewhere in Europe, so that's enough for us to regard you as a native speaker.' 
How on earth am I to reply to this? If having a pointy nose means that I am a native speaker, well, then that's just fine! So I went into that classroom (40 to 50 students = regular size) and tried to answer as many questions as I could.