Going to China

Hi there. I'm from California. I'm doing this thing with my university where I goto China. I honestly never been out of the country nor do I speak any other language other than english or spanish (typical american I know). I was just curious how is it to study in China? Are the people very welcoming there? Is mandarin a very hard language to learn if all I know is english? Any tips at all? Thank you so much I appreciate it.