Let' see what we can do about this, BDDirector.
You can consider creating an upfront deposit or retainer for you to record the donation received before December 31. You might get more ideas on how to do it using this article: Manage upfront deposits or retainers.
Before that, we always recommend creating a backup copy of you company file to ensure your data is safe: Back up your QuickBooks Desktop for Mac company file.
You can restore it if necessary: Restore your backup company file for QuickBooks Desktop for Mac.
In addition to that, your accountant would be the best person when dealing with the accounting activities on your company. They can give you options that will suit your business setup.
Feel free to get back to us if you need anything else.