First thing as in 1936? Thats the earliest start date, after all, and theres plenty of time to NOT be invaded until the historical start of the war. And perhaps this is EXACLTY why Poland should have its own focus tree, to strengthen itself, gain local allies or to appease its aggressive neighbours. If you read the dev diary for the polish dlc, youll see those trails to go down, and how they may even BLOCK Germany or the Soviet Union from certain focuses that end in Polands defeat (though I hope thats not too powerful)