It was handwritten with our share of expenses and income and she sent a check for our share which we just got in March of 2020.
This concerns me, because it sounds to me like your sister is trying to "stick you" with depreciation recapture of depreciation you did not take 2017-2019 as required by law. You did not take depreciation on your percentage of ownership, becuase you did not know the other owner had converted the property to a rental. That means that in addition to paying taxes on your share of the sale price, you will also pay taxes on your share of recaptured depreciation, and will be fined for not having taken that depreciation 2017-2019 as required by law.
So if my assumptions are correct, you need to seek legal advice - and not just from a tax professional either. Overall, your sister who rented the property for three years without your consent or knowledge, should be the one required to recapture 100% of the depreciation and pay 100% of any tax assessed on that recaptured depreciation. Please seek legal counsel, as it's going to be cheaper than the fines and penalties you could potentially pay otherwise.
