Yeah, I second GoNative's concern, me and my friends had a dream of being a band and travel to Japan for a debut...but I'm a writer and teacher now, lol :P Of course, I love your enthusiasm, and I hope that you will be able to go to Japan some day!
Something to think about
: get a financial plan! You gotta have a goal for how much money you need to go there, for one. Plane tickets are around $1,250, if you buy them during off-season (aka NOT the summer or Christmas). Depending on how long you plan on staying, calculate how much each day will cost, where you plan to go, and include travel expenses, food, and lodging. Hostels are very convenient because for around $25 dollars a night, you can stay in Tokyo! It's very nice!
Food's kinda expensive, so try to aim towards $10 per meal. There are cheaper alternatives, which I found out in my thread
here.
And, even though all your friends might not plan on going four years down the road, if you stick to your guns, perhaps a couple of you still will? It's difficult to save money for it, I'll tell you. You'll probably have to save around $2,000-$3,000. On top of paying for school, bills, and books... I found it was very difficult, and just got a loan instead :P
I could say so much more, but I think just taking one step at a time is way better, it's a lot to research, but you can do it! It's great to see you have a clear goal, just continue to focus on it!
Edit: I just realized, I'm assuming you're in America, lol. Of course price of a plane ticket varies from place to place, but still avoid traveling around summer.