Carbo-loading is only really useful for long distances (half marathon and up) and is actually best accomplished by increasing carbohydrate intake gradually over the week before a race. runners-resource.com/carbo-loading
For short and middle distance races, your body's glycogen stores are enough. I always make sure that come race day, nothing is new: no new food, no new equipment, and don't change the times when I eat. Have fun!