Hi Yasmeen,
There are many wonderful places from which you can watch
Wishes (the fireworks spectacular) in the Magic Kingdom. The central hub right in front of Cinderella Castle is probably the best place from which to view the fireworks, but plan to arrive at least 30 minutes prior to Wishes as this area will be crowded with guests. Other great viewing locations include the train station at the end of Main Street U.S.A. and the bridge in front of Splash Mountain in Frontierland. If you happen to be outside the Magic Kingdom, you can catch great views of the fireworks from the beach at Disney's Polynesian Resort and the boat dock at Disney's Grand Floridian Resort & Spa.
To see
Illuminations: Reflections of Earth (the fireworks, water, and laser show in Epcot) simply find a place along the vast railing surrounding World Showcase. As long as you have an unimpeded view of the water and sky above World Showcase Lagoon, anywhere along the railing would be fine. Again, arrive 30 minutes before the stated showing of Illuminations to hold an excellent viewing spot.
Mickey's Backyard BBQ Dinner Show is not in any of the Disney theme parks. Instead, it can be found at Disney's Fort Wilderness Resort & Campground. This resort is just a short boat ride away from the Magic Kingdom.
Best wishes to you, Yasmeen, for a magical first trip to Walt Disney World!
Jill