Back to School---I'm so lost!!

Okay, so there is officially one week until school starts. That means only one week until my oldest starts kindergarten. I'm having the first time jitters, I've purchased all the items for his "supply list" (crayons, markers, folders, binders, tissues, etc), however, I am at a loss as what to get him to wear for his first day of school. He's got clothes in his closet, but I can't think of one outfit that doesn't have a small hole or stain in it. First impressions mean a lot, but do they in kindergarten? Should I get him one new outfit for his first day, and then let the other days deal with the holes and stains? Also, here in burning hot Texas, we won't be able to wear pants or long sleeves for at least another 3 months, so I have to find a nice looking short and t-shirt. I want him to be comfortable, especially since he's never been to school before and want it to be easy for him if he has to go to the bathroom. So, I need ideas on a budget. I have a $10 off coupon for JC Penney, but don't feel like getting him an Iron Man t-shirt. I guess I can go check out the store and see. They do have a couple of cute T-shirts on line... Drummer T-Shirt
So, I'm thinking I could handle my little guy wearing something like this. But then I want him to wear some elastic band shorts... and don't think the Adidas sports pants or shorts would go with this shirt.. or do they?... maybe just some Old Navy or Gap cotton shorts? Does anyone else spend this much time on their 5 year old's wardrobe or am I really that neurotic? Help!! I don't even want to think about shoes!! But you know I will (and have).