Upgrading from Xbox Gold to Game Pass Ultimate

I was wondering if anyone could help me out on the conversion from xbox gold to game pass ultimate. I have seen varying things online and want to get a single solid answer. I have 3 years of xbox gold and I want to upgrade to game pass ultimate but I don't
want to lose 2 years of the subscription. By upgrading to game pass ultimate will I get 3 years of ultimate and then after 3 years have a recurring subscription, or will the conversion from gold to game pass apply immediately and will I lose 2 years?
I would be a first time subscriber and I had friends who were able to upgrade their entire gold subscription to game pass ultimate, which I hope will be the case.

:)