Hi Elizabeth,
I agree with you,
New Fantasyland at Magic Kingdom is iconic. It is such a beautiful area. The theme is absolutely immersive. That said, there might not be too many attractions in New Fantasyland that interest your children, since they are a little older, and some of the attractions there are geared more toward younger children. However, the area is so lovely that I would definitely suggest that you find a way to see it.
One way to see this area for your family would be to dine at Be Our Guest Restaurant, which is a table service restaurant for dinner and a quick-service location at lunch. The restaurant itself is gorgeous. Be sure to try to make reservations as soon as you can if you would like to eat dinner there, or to line up early if you want to eat lunch there - it is an immensely popular location! You could also stop by for a quick bite to eat at Gaston's Tavern, which is amazing. He really does use antlers in all of his decorating! Be sure to get a photo in the huge chair next to the fireplace. Another suggestion that I have for you is to walk through New Fantasyland to get to the Walt Disney World Railroad. The railroad station is located deep in the Storybook Circus area of New Fantasyland. If you can, take this walk at night. New Fantasyland is unbelievable at night! Finally, keep an eye out for information on the opening of the Seven Dwarfs Mine Train. This attraction is scheduled to open in 2014, and will add some thrills to New Fantasyland. Keep an eye on the
Disney Parks Blog for more information.
I hope this is helpful for you as you plan your trip, Elizabeth! Please do not hesitate to ask if you have any further questions.