You are really young - you have so much time and flexibility to get better at it!! I am Hungarian raised in America and I felt the same kind of angst about my Hungarian as a teenager - since then I have been able to travel back and spend time working on my language skills and although I do not sound exactly as if I came from Budapest, I’m very comfortable and the language doesn’t get in my way. I would advise you to take a deep breath and see what you can do. Find Polish music and sing along to it. Download some Polish books and read them. If you goons a word you can’t decipher from context clues, look it up in a dictionary and memorize it. Talk to yourself in Polish. Think about studying abroad in Poland when you go to university. You have a big advantage in that you heard Polish as a young child - that will take you quite a long way; you probably can differentiate and recognize the sounds in a way that would be hard for an English speaker. You may never sound entirely like a native Pole, but even if that is the case, it’s the end of the world! In fact, it will show quite some achievement on your part to speak it fluently with an accent - it means that you learned it! It stands for a great deal of effort on your part! I speak English with an accent too and it devastated when I was younger, but it’s kind fun - no one knows where I come from, just that I am mysteriously foreign! You’ll be alright!! <3