Telling your spouse, children, parents, and siblings is a terrifying experience, and it's not realistic to think that everyone will react positively. But I've known several trans women who have weathered the experience, and, for the most part, it went better than expected. Every coming out is unique, of course, but if there are strong bonds and an honest history of love between you and another, the chances for acceptance and even support are good. Just be ready for the initial shock reaction, some push back, and, if you're like me, a lot of tears. If things go badly, be patient. Some will need extra time to decide what's most important to them.
One bit of advice: Be prepared. Put your words down on paper first in a letter, even if you don't send or hand it over. Have some factual information about ->-bleeped-<- for them to read later. I like the book by Joanne Herman "Transgender Explained (For Those Who Are Not)" $15 at Amazon. Don't get into an argument. You're purpose is to inform them of your decision and why, not to try to change their minds if they don't accept it. That will come later.
No matter how it goes, you are going to feel better having the weight lifted, and your journey begun.
