You want to claim that the Neanderthals were Polish, too? ;)
...before Poland - this land was nothing but land - apparently inhabited by "cheese making" humans. There is nothing to suggest that these "cheese making" humans moved away - but remained on this land - so therefore technically they are Polish - as this land is now Poland - and has been nothing else previously. No other earlier evidence of "cheese making" humans has been found so therefore - they are assumed as "first" ;)