Hi Lucy,
Welcome to Susans, enjoy your stay.
Facing the unknown and staring into a future you can't predict is scary, but many people have done or are doing that now. You should never feel lonely why you are part of this community. There are great people from across the Gender spectrum, great resources (the forums, wiki and chat rooms) and many people who will share their experiences with you.
I know how you feel exactly, I was married, had two children and had to make that choice of disclosure and what that would bring. Well, It is never easy, but if it is truly your destiny then it has to be faced some time or another.
This is a great place to start your journey andas I said, you are NOT alone.
Buffy