If you want to know whether there is, on this website, a tutor whom is a native English speaker, that answer I can't give. I myself am a C2 level which makes me at the same level as a native speaker.
If your question is, is there actually such a thing as a native English speaker? No.
See you can be born and brought up in UK, USA or Australia, but that doesn't mean you are a native speaker:
E.g.: A family (mother, father and 2 kids) are living in UK. Both the parents are born and brought up in UK however the maternal parents are original from Germany (they were born and brought up in UK) and the paternal parents are original from India (they were born and brought up in UK). This means that the children are partial German and partial Indian. However, their nationality says "British" and they are also seen as a native English speaker.
What is native? Just because you were born and brought up in a country it means you are a native?
In USA the native language was not at all English and yet if you're a US citizen you are considerd as a native English speaker though your anciensters have their origin from another country.
Everyone can adapt a language as good that they can become a native speaker. Hence, this is the fact for me. I'm a Belgian native which makes that my mother tongue is Dutch. During my studies I got to know more about the English language which eventually made me come at the C2 level which is the highest level a "non-native" can achieve. This C2 level is equal to the level of a "native" English speaker.
Now I have mentioned the word "mother tongue" that is a much better word. As it refers to the language that was taught to you since you were a baby and which is also used as a medium in the schools you went to.
Conclusion: there is no such thing as a "native English speaker", however, a person who's mother tongue or first language is English is correct.