Your particular family dynamic is key.
At twenty-one, I left home and cut all ties WITHOUT telling my parents I was trans. I knew that there was such a thing as MTFs, but I didn't realize that it could go the other way.
My brother eventually gave them my contact info, and after a nasty struggle, I started sending letters to my folks, mostly out of guilt. Several years into that, I realized that I was a transsexual, but I thought that meant mental illness, so I started labeling myself a cross dresser (the book I had didn't say that women who dress as men are mentally ill). I still didn't tell my parents.
After a few more years of this (maybe five), I was finally calling myself transgender, but I reached my limit and could no longer write letters to my parents. I cut them off again, this time for about twenty years. If my father had been divorced or a widower, I wouldn't have done that. I can't stand my mother. She is very traditional and conservative. Unless she has changed radically, she is guided by conservative religious beliefs.
My father tracked me down, and I reestablished contact with him alone. I am living as a man now, and I came out to him a little while into the relationship. He was thrown for a loop, but he hasn't cut me off. However, he has kept me a secret from my mother. As far as I know, she doesn't know that he is even talking to me. He recently dropped me a note to tell me that he is still figuring things out. He didn't say that in so many words, but it's what he meant.
I have mixed feelings about the whole mess because, frankly, I want nothing to do with my mother, but my parents have been married for sixty years and aren't going to divorce at this late date! So it's a package deal. And I don't even know quite what I want from my father, either, so I'm further confused by my inability to figure that out.
As you can see, this has been a thirty-year ride that isn't over yet, and it has been affected by so many variables that I still haven't teased them all out. No two families are alike, so you need to figure out and act on your own variables. You can sort out some of this stuff with a professional. See if you can figure out exactly what you want and why. And don't burn your bridges. Think carefully about coming out and when you come out, since you cannot stuff that genie back into the bottle. And don't forget that your fortunes can turn. Some time after I cut my parents off for the first time, I was broke, hungry, and thiiiis close to being homeless. I wouldn't have asked for financial help from them under any circumstances, but you might feel differently in a similar situation. And I should point out that a lot of parents surprise their kids and become accepting, even if it takes a few years.
Think carefully, talk to someone, plan, and make conscious choices and not kneejerk reactions.
