I didn't do it for graduation, but this summer I invited two friends along with me. It was sooo much fun! You'll have a great time! One of my friends went there a few years ago, and the other one has never been there. So I made sure to do all the popular rides. I went to the summer, so it was kinda busy, so I made sure to do all the popular rides first, then do as many of the rest as possible.
If your friends are first timers to WDW, make sure you take some breaks. It gets overwhelming and tiring. And if you can, make sure you take a day off from the parks to recoup, like mid-week. That helped a lot.
A good tip: If you and your friends don't want to see the fireworks, it a great time to hit rides. Me and my friends didn't want to watch Spectromagic and Wishes at Magic Kingdom, so we hit Space, Splash, and Big Thunder Mountains multiple times during that time. Very fun!!