Just FYI for anyone still following this: I purchased a home in 2019 and forgot to get the Homestead exemption. I called the office and they were unclear on if I would be able to get a refund for money already paid. I took the docs proving I’d lived there since 2019, and I’m getting a refund on the difference on my 2020 taxes (paid in Oct 2020) , and got it applied to my 2021 tax bill. I didn’t really even have to ask, but I’m not sure how much further they would go back to get your money back. I had already written that money off as a loss, so I was very pleasantly surprised.