Hi Melinda,
It sounds like you have a great trip planned to Walt Disney World. Traveling with a large group can be so much fun, and celebrating a high school graduation should make it even better!
With a larger group such as yours, I suggest that you split up the group from time to time. Chances are that there will be times when you all do not want to do the same thing. Go ahead and take some time apart in the groups that make sense. If part of you are interested in doing thrilling attractions such as The Twilight Zone Tower of Terror while others want to take in shows such as Beauty and the Beast - Live on Stage, then split up the group for a few hours to do so.
It is interesting that you mention dining, because with a large group, I suggest that dining is the time that you can come back together. You can split up for the morning and make a reservation for lunch around 1:00 p.m., at which time you can all join back together for a meal and talk about your adventures. Since you mention that Star Wars Weekends at Disney's Hollywood Studios as a must, I would suggest a meal at
Mama Melrose's Ristorante Italiano. I really enjoy this large, casual Italian restaurant. As for other restaurants to enjoy with a large group, I recommend
Trail's End Restaurant at Disney's Fort Wilderness Resort & Campground. The fried chicken is fantastic.
'Ohana at Disney's Polynesian Village Resort offers delicious Hawaiian fare and is also great for large groups.
I would love to help you plan more Melinda; however, I am limited in the amount of space that I have to answer. Please do write back if you have any further questions!