Hi Sandra, and welcome to planDisney!
I see that you have an upcoming
Walt Disney World Resort vacation on the schedule; congratulations! What fun you and your family are about to embark on.
I understand your disappointment that your desired theme park is unavailable to reserve for your arrival day. The best bet, in this case, would be to keep checking as an opening could appear at any time as guests may cancel, etc. If you cannot make your theme park reservation, you can always reserve another theme park and then visit
Disney's Animal Kingdom Theme Park after 2:00 PM, as long as they are not at capacity and you have the park hopper option added to your theme park tickets. You will need to visit the reserved theme park first in order to visit your chosen theme park after 2:00 PM. You will not need a theme park reservation when you park hop after 2:00 PM.
Please let us know if you have additional questions.
Have a magical vacation!
Raquel