USA, Canada / Can Polish people go to university in the USA (easily) ? [22]

hi im not american but i live in america and go to univ of us now however i used to live in uk before came america and i have got a polish girlfriend in uk.but she is still in uk and she is going to come america for univercity and stay with me someday.

i heard that it's hard to get an american visa for polish people so im worring if she won't be able to come here.