I’m starting the process to immigrate to the UK soon and I don’t know how to tell my family.

For context, I’m Canadian. I’m starting the process of immigrating to the UK soon but I have a bit of an issue, my mom has been very controlling my entire life and even in my adult life it’s caused some issues. Both my parents want to build me a house right next to ours because of the housing prices, which I VERY much appreciate, I’m just worried it’s going to seriously harm the relationship between me and my mom. I decided a few years ago I would leave Canada as soon as possible, but I never had the heart to tell her as I know she will be both angry and sad. Now that it’s getting closer to me going through the process, I need to tell my parents soon. But I have no clue how.