charris0n, don't worry.
At this age children do not LEARN language but ACQUIRE it in a more natural way similar to that of acquiring their mother tongue. Therefore, they learn it fast and relatively effortlessly. I think you should help her by non-verbal communication rather than trying to speak Polish.
I've never met anyone who would like to sent his/her child to english school without any knowledge about this language. It may appear very difficult for you to start. Actually it's almost impossible to learn this child english without any basics.
If you knew some psycholinguistics basics, that wouldn't seem so scary. I even heard an opinion (from a specialist), that if you want your children to speak English better (especially in terms of pronunciation) and you're a foreigner, you should not speak English at home at all lest your children take up your foreigner errors and accent.