How did you tell your transphobic parents you were going on T?

I mean, the title kinda explains it.

I am 21 years old, and I am hoping to move out this year with my two partners. I have been out as trans since I was 16, and I have absolutely no regrets and will be hopefilly going on T in the next few months! I'm so incredibly tired of waiting, I have never felt more ready. I have a stable good paying job, and I will be paying out of pocket because I am still on my parents health insurance. (From what I've seen, it's probably easier and not really that crazy expensive anyway)

My parents have never been supportive. More so in a "please stop we love you" type way, not a "gonna kick you out" type way. I have been having a hard time deciding if I should TELL them I'm going on T, or just do it and let them slowly notice. I almost feel it's better to tell them, because they will be HORRIFIED when they realize. But I'm also scared they will flip out and do everything in their power to stop me from doing it. I was wanting to hear other people's stories, and feel a bit less alone in this struggle