Investors & landlords

Thanks. I'm going to try to get the answer I want one more time :).  This is about capital gains only.  This is probably wrong, but I have a hard time giving it up.

 

 We bought the house in 2020. We have never rented it. Since 2020 it has increased in market value by 25% (crazy market in the pandemic). Up until now, it's been a personal property. So it seems to me that, to be fair,  the starting figure for capital gains purposes should be the value of the house on the day it becomes a vacation rental or pure rental property, not the price we originally paid for it.  That 25% gain in value occurred when the house was personal property. That's logic, but I'm not sure it's tax law.  I want to claim the value of the house at time of rental, not the price we paid. Regarding cap gains, is that wrong?