Graduating from a medical school is only one step of becoming a practicing physician. After the school you will need to pass USMLEs and so on. These exams are not easy.
I suggest to think twice before investing 4 years and a lot of money. Medical schools require a lot of effort and self sacrifice.
I have graduated from Poznan in Poland and work as a physician in the US.
A few of my fellow students resigned and returned to the US, some transfered to the US schools after 1st or 2nd year.
A few graduated but did not pass the USMLE exams.
Personally I got sufficient education in Poland to pass exams, get into a residency and to get licensed as MD.
What you should do? Test yourself with MCAT and see where you are.
Good luck in whatever you decide.