-Molecular Biology program
-International student
-Not crazy about parties but few once in a while are cool
Better teaching? Better campus? Nicer people? 
All I know is that Penn State is higher in rank
Also I’d like to have a way to change majors later just in case
For an international student, I think Penn State would be better: better location (about 5 hours from New York City, Philadelphia, Washington DC, and Baltimore) and greater variety of majors (12 different colleges from Science to Communications to Business to Arts to Engineering, whereas Purdue is Indiana’s STEM school) which in turn means a greater variety of student profiles.
Purdue is about 2 hours by car from Chicago or by Greyhound Bus. Lafayette also is on an AMTRAK line to Chicago.
Penn State is not on a rail line, but there are connections by Greyhound Bus and Megabus. Philadelphia would be about 3 1/2 hours by car.
https://www.greyhound.com/farefinder/
http://www.amtrak.com/home
http://us.megabus.com/