The mere fact that your a native speaker speaks a lot of your proficiency ! You would be astonished to know how many "teachers" there is in my country who think they can teach english and they can't say simple things right just the same. Like one teacher who was in teaching business for well over 20 years, once said in front on me: how would you call it (she meant "what do you call it").
I would rather pay you twice as much as I did her and learn your correct, natural grammar along with your spelling mistakes, than pay my previous teacher and learn her whacky, out of place, english and her perfect spelling.
Just remember this: spelling doesnt mean **** - if you cant see the difference between hair and hare or between your and you're - that's fine with me. I'd just aw well write "your" in leu of "you're", so long as my grammar is natural, so long as I don't say stuff along the lines of "how do you call it", or ever worse "I know what do you call it".
Take care, and be persistent, you'll make a nice teacher !
You're the best teacher possible only because your a native speaker !