[simplechamp]

I would at least wear a Polo/collared shirt, and khaki pants. You don't need a suit or anything, but a plain white tee and jeans seems a little too casual.

Doesn't matter if you are young and it's just a summer job, you want to show them you make the extra effort to look your best. No one is supposed to judge or base hiring decisions on appearance, but we all know in the real world that's BS, you are judged on your appearance in a big way. Better to be a little overdressed than underdressed.