It can be as safe or dangerous as you want it to be. Having spent 20 + years in the USA, I would say it is safe. Like someone else said, PA is large, where are you going to study? It is a beautiful state, with gorgeous rural areas, bustling city, and lots to do. Outdoor activities are great; it is a hop-skip-and-jump to the New Jersey shore, New York City, and not far to get to Montreal in Canada. I would say if you have the opportunity, you may as well do it.