Going to college in and of itself demands leaving your comfort zone. For your entire life, you have known the comforts of your bed, your house and your hometown (however much you hated it). The next thing you know, you're sleeping on an uncomfortable twin-xl covered in noisy green plastic, in a dingy dorm room with terrible lighting, on a campus and in a college town you don't know your way around.
Needless to say, leaving your comfort zone can be straight-up terrifying. We become so used to the way things have always been, and when we leave that, we have to figure out an entirely new way to go about our lives. In college you have to figure out how and where to study; how to ignore the stares as you walk to and from the shower in nothing but a towel and have to pass your building's lounge along the way (been there, done that every single day of freshman year); and how to find a quasi-healthy semi-balanced meal among the sometimes limited offerings of the dining hall (you will give up and eat fries for dinner).
But besides the comfort zone that you are virtually required to leave in order for you to function in college, there are also the more subtle comfort zones that you may not leave as easily. They are accessory comfort zones, if you will, and while leaving them is not essential to surviving in college, leaving them is essential to thriving in college.
There is the comfort zone that tells you not to strike up a conversation with the student sitting next to you in class; it says, "Don't be weird, don't come on too strong." There is the comfort zone that tells you not to go to the party in your building hosted by the kid you have never met; it says, "You don't even know anybody there; don't go, it'll be awkward." There is the comfort zone that tells you not to try out for that club sport or audition for that play; it says, "You've never played/performed before, don't even bother." There is the comfort zone that tells you not to rush a Greek organization; it says, "You're so shy with people you don't know; you'll never make it through."
You may not need to leave these comfort zones in order to survive in college. But I can say with utmost confidence that if you want to enjoy college and make the most out of your college experience, you must leave these comfort zones.
Talk to the student you don't know; you could have a ton in common and end up finding a new study buddy. Go to the party; you could end up finding a new friend or two, or a whole bunch! Go out for the new activity; you could end up finding your new passion or talent. Rush a Greek organization; you could end up finding your home on campus.
In the words of Shia LaBeouf, just do it. Ignore the fearful, anxious, nervous thoughts clouding your brain, and instead think of all the wonderful benefits you can reap from doing something uncomfortable. College is the time for trying new things, and if you force yourself out of your comfort zone, I can guarantee that you will be so glad you did it.