What an incredible surprise for your daughter's birthday, Annmarie!
To help with finding possible dining options, it may be best to call Disney Dining directly at 407-WDW-DINE and just ask what is available for the size of your party on a specific date at a specific location. If you are flexible with times, you may be able to stumble across something an unexpected opening. Also, September is still far enough away that there could certainly be changes happening. So if you have your heart set on a certain location, you can check for availability frequently.
To help with further ideas, there are actually a couple of questions where many of us here offered our options, which should leave with you plenty of alternative ideas of how to celebrate. Just click
here and
here to read those questions/answers. While the second question is geared toward adult guests, there are still plenty of ideas for a 14 year old to enjoy.
Please let us know if we can help with any more questions. Wishing your daughter a magical birthday!