Hi Wendy,
How lovely to want to take your teenage daughters for a special night of fireworks viewing. I have a few options that might work for you.
Since you considered California Grill but do not think it is quite right, let me suggest another restaurant,
Narcoossee's. It is a nice restaurant at Disney's Grand Floridian Resort & Spa, but it is a little more casual feeling than California Grill. The menu is seafood-heavy and delicious. If you are able to time your reservation around Wishes Nighttime Spectacular, you will have a great view of the fireworks. Even if you are not able to sit at a window table, you can go out on to the porch and get a great view.
You could also have a very special fireworks night by booking a
Fireworks Cruise. This specialty cruise would include a lovely boat ride on a boat just for you and your girls. The boat will stop in Seven Seas Lagoon with a great view of Cinderella Castle for the fireworks. To book a Fireworks Cruise, you can call 407-WDW-PLAY (407-939-7529).
Finally, consider the
IllumiNations Sparkling Dessert Party. This is an in-park party at Epcot with a great location for viewing IllumiNations: Reflections of Earth. Although this is not at Magic Kingdom, it is a great party with a great show and wonderful dessert. You should know that sparkling wine is served at this event for adults; however, it is still quite appropriate for those under 21 as well. I took my daughter to it and she loved it.
I hope that these ideas are helpful for you, Wendy. Please do not hesitate to ask if you have any further questions!