I am slowly coming out to people that I know that I am a transgender woman and most have been very supportive but I have only come out to my birth mother who I haven't seen in over 20 years and she was very supportive but then I came out to a few gay friends and they were accepting as well. I am not sure if I have the courage to tell my dad and my stepmom and the rest of the family. They already know that I am gay since I came out when I was 22 years old.

Perhaps when I do start to transition and go down that path to dressing FT and what not I will get the confidence built up within myself to tell everyone then or just show up dressed as a female and see how they respond, lol

I don't gamble but if I did, I would bet that a lot of people in your dad's family are going to say "I knew that already" when you come out as transgender.  I really wouldn't worry about it if I were you.

I don't know how they would say that they would know that already when I really don't have the manners that would suggest that I am transgender or given them any hints that I am.

I came out to most of them that I was gay and they were shell shocked and were totally not ready for that at all. Perhaps you are right and if you are that would be great. Cause family means so much to me.