It will all be alright. I was a freshman in football last year , just listen to your coach and have friends join the team with you.
Get ready for the time of your life, your going to have alot of fun!!! You will learn all you need to know there. If you wanted to buff up on you knowledge that is always good to do, I'm sure you could find a general ed book on the game and rules, but you don't have to. Of course it would be good and I recommend that, it will help you, but I wouldn't worry about it short term. Have FUN!!
Yes, you will be fine........