This first.
Then, class difficulty depends on your degree; some might be easier than high school, most more difficult.  if you're outgoing and know anyone, there will be parties, how hard you party depends on your enthusiasm haha.  there are girls in all places; if you end up at a place with really drunk girls there will be drunk bitches.  there is always "that one girl," or several of them, basically it depends on who you are if you're lucky or unlucky to be associated with them--watch this differentiation, usually those girls aren't all that highly thought of in the grand scheme of things, but it's obviously case by case.
don't waste your time and money if you aren't motivated by your studies.  I know plenty of people who graduated and who didn't graduate; for the most part, 1-2 years after dropping out or graduating doesn't really correlate with "having a job" (related to their degree).  make it count though, it's a shitload of money; but don't forget to get all you can out of it and have an awesome social life at the same time.
college of not you'll (hopefully) have fun and learn something.