Donating to nonprofit before it receives 501c3 exemption

Hello,

 

I am considering donating to a nonprofit which is in the process of receiving 501c3 exemption, but has not yet received its exemption. I understand the law says that donations made to an organization before it receives 501c3 exemption do become tax-deductible when it eventually receives 501c3 exemption. However, the timing of this process is not clear: if I donate in 2021 and the organization receives exemption in late 2022 after I've already filed 2021 taxes, would I claim the deduction against my 2021 income (since I made the donation in 2021) or against my 2022 income (since I would have already filed 2021 taxes without it)?

 

Thank you so much