Hey Danielle!
Welcome back to the Disney Parks Mom Panel! Thank you for this great question.
I am a huge fan of the
Tomorrowland Terrace Fireworks Dessert Party. When I first started attending the party years ago there was no rhyme or reason as to when reservations opened up and your best bet was to watch the DisBoard for the announcement. However, those frantic days are now over. Starting in late 2013, the reservation policy changed and you can now book your party reservations 90 days in advance.
To find out when you will be able to book all your advanced dining reservation there are some great ADR calculators online. You can search Google for "ADR Calculator" and it will return several great options. My favorite is the calculator offered by WDWInfo. It not only calculates 180 days, it also does 365, 120, 90, 60 and 30 days. That sure beats counting backwards on your desk calendar.
I hope this helps with your planning. If you have any other questions please come back and see me.
Wishing you a magical vacation and pixie-dusted day!
Sue N., IN