Counting age in Poland?

I hope this is the right category. In America, your counted as 0 years old at birth and 1 year old a year later on your birthday, but in some countries, you count as 1 year old at birth and 2 a year later, or even 2 when the new year comes. What's it like in Poland?

My wife is 28 years old and was born in 1993. Hence, I believe, Poles count also year zero as 0 years old.

Same in Poland