Granted, you probably need a cover more than me, with soccer and school and all. That said, I'll share this. I kept my Motorola Droid X, my first ever cell phone, in a case from darn near day one with a screen protector on it. Before I got the case, I carried it in a sock. Well, yeah...I didn't want to damage it.
After carrying it like that for two years, and as I was packing it up because I got my S3, I rediscovered how nice of a phone it was...which was kind of honked up by the large case. Then it dawned on me that I got a case to prevent cosmetic damage to the phone...but the case would have covered any cosmetic damage. So, with my S3, I figured that I'd just wait until a got some damage before I'd get a case. So far, so good. The glass front is great, and the plastic back - even if it got damaged, which it hasn't - would cost about $10 to replace.
My point? Maybe give it a try without a case first.