Being one of those students who was involved in everything my senior year (well, not everything, but close), I easily could have come into my freshman year of college thinking, "I'm going to seize every opportunity that comes my way!" Fortunately, I had people giving me advice before I went into college, so I knew that that definitely wasn't going to happen.
At the beginning of freshman year, in fact, I hardly pursued anything. Men's Chorale (aka "man choir") was the only thing I committed to prior to college. I knew that things were going to get crazy, and my studies were going to be more difficult than high school. So, I took it little by little. A leadership opportunity came up? I applied. A chance to be on worship team? I auditioned. There were two other things aside from these I applied for, which was really good for me. I kept my involvement to a minimum.
I didn't get selected for one of the leadership positions I applied for, but I did make it into everything else. I'm not saying this to brag (sometimes not making it into something can be a blessing in disguise), but it turned out to be the perfect amount of involvement for me. Each of the things I made it into required only a few hours a week, with a few more hours on occasion.
Long story short: don't overload yourself in college. If your studies take up too much time, don't get a job. Don't stress about it. If you can't apply for that leadership position because school and work take up a significant amount of your time, don't worry about it. It's only freshman year, after all. Before you know it, you'll find your ground and know how much you can handle.
On the flip side, get involved. Doing absolutely nothing except school is a little ridiculous. Plus, you want college to be fun, right?
Get out there. Have fun. Get involved.
On the same token, focus on what you need to. There's no need to overwhelm yourself. After all, this is college. It should be the best years of your life.
(So far.)