You will find that most of the grads will be staying at the all star resorts, so if you will be staying there beware...We did a couple of years ago, and they were very rowdy in the evenings, even doing some damage around the pool area(we were at Music). I would go again during that time, only stay somewhere else. We had no problems in any of the parks. If you are interested in getting more info about what will be going on during grad nights, visit disneygradnite.com. Hope you have a great time.
Laura