This is a great question! I would recommend that you call soon and you should be very pleased.
I recently made my June
Advanced Dining Reservations (ADRs). I was able to get almost all of my preferred dining times which was a pleasant surprise since I'm only 4 months out from our vacation.
Note that most restaurants begin accepting reservations 180 days in advance by calling 407-WDW-DINE (407-939-3463).
Chef Mickey’s and Donald’s Safari character meals had availability too. I wasn’t surprised that Cinderella’s Royal Table did not have availability for an early lunch but I was still able to make a later reservation. I also got a 5 p.m. reservation at the Hoop-Dee-Doo Musical Review and the Grand Floridian’s Pirate Adventure (for my son) which I didn’t think would be possible.
For finer dining, I had no problem reserving the Hollywood Brown Derby.
Interestingly, the Cast Member at first thought I was booking for a party of 3 and she said the first seating she had available at Chef Mickey’s was at 8:25 p.m. When I told her it was for a party of 4 (good thing we are bringing “Grandma“), she could book us at 5:05 p.m. That’s a huge difference!
Good luck!