Will Polish people be accepting that im only half polish?
Just go as yourself and you'll be treated accordingly...
If your distant ties to Poland convince you that you need make no effort to fit in when you get there, then I suppose that could be a mistake. Remember, you have never lived in that country and need to learn about it as any outsider would...
Your reasons for going there and your assumptions when you arrive may hinder any real value in your relocation. Just be open and tolerant... as you would act toward any outsider from your own neighbourhood... ;)
Polish are on the whole an educated people, and for reasons possibly directly related to their having not much experience with multiculturalism in their homeland, are, I guess, more curious and open to the idea of cultural assimilation than, perhaps, communities where the "reality" of multiculturalism has exhausted any real efforts for it to function in any idealistic sense.
Just give Poland a little more credit, that it will not just enthusiastically harbour individuals who prefer a white majority... more than it will say, harbour individuals who have gone to their country expressly because they have made this assumption...
But overall... Good luck. :)