Probably the best advice I got was from an advisor
was that there'll be jobs for people who graduate with like a 2.5-3.5gpa in engineering...anything higher will probably be doing research/phd.  Moral of the story is, the people who will become engineers are the ones who perservere (sp), just kept at it day in and day out.
You're gonna get frustrated, you're gonna be disheartened and question yourself a lot for the first couple of years...hell you might even suck at drafting in your intro to engineering course.  Just have to keep on dreaming about that day when you graduate and all your hard work pays off.  Honestly, the material isn't so bad if you keep an open mind and do enjoy math/science a lot.  It is what makes staying up those nights worthwhile.
I was somewhat lazy in highschool and didn't have much of a work ethic...if you want to stay alive in engineering that's all gonna have to change.  
I haven't had a difficult time maintaining an active social life...but I'll only go out once a week, whereas I have friends who will party from thirsty thursday all through weekend.
I still have plenty of time in the day to nef on anandtech 

, play tennis/soccer, work out yada yada.  
There is just simply no time to procrastinate.  You'll really need to get into the habit of not taking naps, doing work right after classes while stuff is still fresh in your memory and studying during the day..not the night.  You will have to be very organized and really plan out your daily schedule...otherwise you'll just put stuff off and be up to 2-3 in morning doing crap.
I'm just getting into my EE courses and I struggled a lot my freshman/sophmore year.  I'm a very active/social person and finding the right balance has been difficult...but you'll get there eventually.  Personally, I can't see myself in any other major which makes me think I choose the right thing as the only other place I could see myself would be going into medicine and med school would be hella lot worse 

.
What they've been saying about lack of girls is very true.  Hopefully...you're not a huge introvert/geek 

, and in your elective courses like psych/history of rock and roll/whatever you can chat it up with the opposite sex.  If not, join some clubs as that's best way to meet people with similar interests.  And party.
I honestly wouldn't worry too much about what people have been saying.  Engineering is very tough and it's not meant for everybody, if you're not serious about it then you should not apply as you'll be miserable...probably why people try and scare others off haha...unfortunately you won't find out how serious you are till about a year or two in and maybe after an internship/coop ;0 
try and find a parent of someone/talk with a professor and ask what it's like in real world/doing research.