I can understand all too well. That's a big part of what kept me from admitting my trans status to myself for over 30 years; fear of parents'/extended family's reactions.
It took me until now to realize that either they love me forever no matter what, or they aren't strong enough to love me. I deserve to be happy. In order to do this, I *need* to have my outsides match, as closely as possible, my insides. As a grown-up, it is up to me to pursue happiness, and I'll just have to hope my family and friends can keep up.
It is different, though, for everyone, and some people just aren't ready/able to take that step. This is where a therapist comes in handy. They can give you tips on coming out, on abating your fears, and they can help you hold things together if you are rejected. Better still, if they're worth their salt, they can help you realize you and your needs are important, and that you, yourself, have the right and ability to be happy no matter how people react to you.
*hug*