Long runs will be pretty hard. Just make sure to stretch before and after runs and stay hydrated. If you drink too little you'll get cramps and if you drink too much before a run you'll get cramps. Pace yourself and focus on getting through it.
It will most likely be the best experience of your life because majority of the people are just like the people here, and after you get home from practice you can eat whatever you want and not feel bad about it!!!
I was supposed to join, but it starts in the summer and I wasn't looking forward to running all summer, or dying. Lol, just kidding. But from what my friends on Cross Country tell me, its no joke. It takes a lot of endurance, stamina, discipline, and commitment. I've practice a little before thinking i would join, and at 2 miles, I literally died. Don't give up though, and make sure you stay healthy.