There is a little saying I've heard regarding college: "Good grades, social life, and sleep: pick two." For some people, and for some majors/courses of study, that is more true than others, especially depending on your definition of "social life." Expect a minimum for one hour of homework per hour of class (for some classes the ratio is more like 2 or 3:1) in order to keep up. In the U.S., in high school if you are fairly gifted intellectually you can put in near zero effort outside of school hours and still do well (that's what I did. HS GPA 3.65 or so). In college that is *not* N-O-T true (I learned that the hard way, GPA freshman year 1.2).
All that to say, you will need to prioritize. No one of us can tell you what you will or won't be able to do-- we don't know your abilities, the difficulty of your coursework, etc. Ultimately, however, it doesn't matter as long as you prioritize so that no matter what you do or don't have time for you can look back on your day, week, year, or entire college experience and think, "I may have had to sacrifice X amount of Y, but I can be proud of my accomplishments in Z and Q etc."
Take it from someone who's grad school options are now limited: think ahead to your life*, career path, etc and go into it with a plan of what is important and what isn't so much and stick with it. You'll likely end up changing your mind (especially re: career, if you're the typical college student) and re-evaluating, but after you've re-evaluated stick to whatever your current plan is as best you can.
As long as you don't let it go completely off the rails, you're going to love college. Good luck and have fun!
*note the inclusion of factors other than career path. Grades are important, but they're not everything. :)