Nicole, having breakfast before the parks open is one of my favorite things to do while visiting Walt Disney World! It is so cool that you were able to get such a highly desirable reservation time. Looks like you have a bit of pixie dust before you even arrive!
Once you arrive at the park entrance, simply look for a Cast Member holding a tablet. She will ask you for your name and check to be sure you have a reservation and she will allow you to enter the park. If you can't find them, simply ask another Cast Member where you should go for your early morning reservation.
The early bird certainly gets the worm! On your way to your reservation, take the opportunity to enjoy the sights of the park without the crowds. If you are at Magic Kingdom Park, take the time to really notice the details of the windows on Main Street U.S.A., and be sure to get a beautiful and crowd-free family picture in front of Cinderella Castle!
Wishing you and your family a magical vacation, Nicole!
~Rachel