Fixed that for you.
I wouldn't worry if I were you. Your English is probably way better than that of the average
Pole Byelorussian Mississippians.
This is too often true. My German neighbor offered to teach me German if I would teach her English. I pointed out that she already spoke better English than I did. That was very disappointing for her, so I offered to teach her bad English instead. It was a deal.
I remember once listening to a couple of young American natives making fun of a Sri Lankin student for speaking accented — only slightly accented — English. "Done come hir if yu cain't spake Anglish," one said. I resisted the urge to point out that our mutual acquaintance not only spoke English more eloquently than the natives, but he spoke at least two other languages as well, something the other fellows could not boast. I wish I hadn't.
On the other hand, it might not be a bad idea to teach regional dialectal and colloquial variants to someone learning the language. I recently had a conversation with a co-worker about southern Louisianaian culture that we had to turn around and translate for a third member of the conversation who was from upstate New York.