Hi, Rocio!
Not to worry!
At any Walt Disney World park which offers reservations prior to the park's opening (Advanced Dining Reservations, tours, etc.), there will be a clearly marked portion of the main gates which are specifically set aside for Guests with early morning reservations. Just tell the Cast Member there your name or confirmation number; he or she will locate your reservation on a list, and you'll be allowed early entrance into Epcot.
Be at the gate no later than 8:15 if you have little ones in your party (whose little legs might take a bit longer to walk to Akershus Royal Banquet Hall, in Epcot's Norway Pavilion) or if you'd like to stop for some great photos of the park while there are very few people in it. (Breathtaking!) This will allow you a more leisurely walk to Norway (walk straight until you come to the lake in the center of World Showcase, then head left.
Akershus Royal Banquet Hall will be the second country on the left. ;-) )
Have a wonderful breakfast, Rocio! Be sure to have your camera ready, and autograph book open, too. Those Princesses love to greet Guests and pose for pictures throughout the morning; you're in for a wonderful experience!
Send more questions as you think of them, too. We love to help!