USA, Canada /
Moving to Poland from Canada [40]
Spoken as a women:
A lot depends on your personality and expectations. You have to accept things will be completely different. Sometimes better, sometimes worse.
I think the social interactions in Poland are healthier for kids. Bonds tend to be fewer but stronger. At such a young age they shouldn't have slightest problems adapting.
Financial side will depend of course on what you guys can do for a living, are you both going to be working etc. But generally you probably will be a bit worse off.
You will be isolated unless you will really make an effort. Go out every chance you get. Accept invitations etc.
It would be good if you had someone you could observe to learn stuff. As Maf mentioned even shopping.