Hi Carol,
I can't recommend enough finding a therapist who specializes in gender issues to talk to. I did this as a first step when I got to a similar place you're at right now and it has helped me a ton. Coming out is one of those things that once it's out there it can't be taken back, so you really want to plan it like you would plan any other major life changing event. I haven't come out publicly yet, but my family knows and I think that because I took some time to find the right moment, and talked with a therapist about it that the whole coming out process went really well. So far I have had a couple close friends, and my family be 100% supportive and accepting of me. When I do go public I expect some won't take it well, but I hope to be in a place at that point where it won't matter.
As your first step I really strongly recommend seeing a gender therapist if you can. It's so helpful, especially if you are considering coming out. It's good to have that support system established behind you as you go forward.
I know the feeling you have, and I really wish you the best as you take your next steps.