My attempt was "I have never been to church" is this wrong? to me it sounds more fluent English than the given correct answer.
Firstly, the English sentence is truly strange indeed. We will change it to "I never used to go to church".
Secondly, your interpretation seems a bit too much. The Polish sentence means that "I have never been a church-goer", but that doesn't meant that I have literally never been inside a church and unless I'm wrong, that's what your sentence would mean.
So, for what it's worth, my translation was 'I have never been to church'. I think that 'I never used to go to church' might imply a different state (such as 'but now I do go to church').
I think it's a possible interpretation in Polish, adding the part "ale teraz zaczęłam" (but now I started) is an option. Meanwhile, "I have never been to church" really is too much, it's actually pretty unlikely - even if you're a non-believer, didn't you ever attend anyone's wedding or funeral?