I majored in journalism, specializing in news/editorial and minored in communications at the University of Oregon and LOVED it. The classroom size and atmosphere will depend entirely on the university you choose to attend. Most typically when you're just taking prerequisites (classes like econ & grammar that everyone has to take to graduate) they will be much larger. Once you choose what specialty you'd like to pursue with journalism (like PR, News/Editorial/Broadcast, etc.) then classes start to get smaller and more intimate. These are the classes you benefit most from because you get more one on one time with professors. No matter where you end up going to college, Journalism classes are energetic, collaborative, and creative environments.
If you're having trouble deciding between journalism fields, I recommend taking the variety of journalism classes you take your freshman year seriously. Really pay attention to what subjects you enjoy learning about. Talk to your professors after class and ask them questions about what it's like in each profession you're considering, and which specialty they think (after seeing some of your work of course) would be best. Also come to CareerVillage! Ask professionals on this platform what it's like doing what they do on a day to day basis to determine what career path is best suited for you.
No wrong decision here, thankfully:) Journalism is a GREAT major and everything you learn will be valuable post college. Although my degree is in news editorial, my options after graduating were really limitless. Unfortunately for me, I figured out a bit too late that the life of a news writer just wasn't one I was cut out for. I was already well into completing my degree. I encourage you to do the research now to figure out which path you are MOST interested in pursuing so that life after graduation is a bit easier (and more fulfilling most importantly!).
Best of luck. Please don't hesitate to post a comment if you have any questions for me.