I have the 12 inch and I really love it - but I have back and shoulder problems and the 17" was too heavy for me to carry around. The 17" would be better to look at everyday - but one thing to think about is that, even with a 17" screen, web pages and word files do not fill the 17 inches - so even though the screen is bigger, what you are looking at is not necessarily bigger. Just something to think about - plus carrying the laptop around all day in your backpack is also a consideration. I think smaller is better - but that is just me.
I think a laptop is an absolute MUST for any college student!!! My students use them in class to take notes and then they sit in the lounge and work on them between classes. And we have wireless internet (most colleges do) and so you can check in on YT too!
Is there an apple store near you? We have one in the mall here in Austin. If I were you, I'd go to an Apple store (if possible) and just play with them. I think you will love it - but you should check it out!