Hi Michael,
What a wonderful way to spend your 19th Birthday!
There are many special dining experiences available at Walt Disney World. You can find out more information about what is on offer
HERE
If you are considering a dining at a Signature Restaurant, I can highly recommend
California Grill which is located on the 15th floor of Disney's Contemporary Resort.
The food which is prepared in an on-stage Kitchen is absolutely delicious and the restaurant itself, offers stunning views of the resorts situated on the Seven Seas Lagoon and Magic Kingdom. I would recommend making an advanced dining reservation for up to an hour prior to the start of Wishes on the day of your meal as there is an outside viewing platform where you can watch the fireworks whilst listening to the soundtrack which is piped in. We ate here for the first time last year and really enjoyed it!
The easiest way to make a reservation is online (as detailed in the first link)
Simply enter the name of the restaurant of your choice followed with the date, time and party size and click on 'Search for a Table' When you are taken to the next screen, select the time of your choice and click on 'Reserve' and follow the on screen instructions. Be sure to keep a record of your reservation number and take it with you to your meal.
I would highly recommend that you make a reservation as soon as possible as you will be visiting at a busy time of year where many restaurants will get booked up.
Wishing you a very happy 19th birthday and magical holiday!