Hi and welcome. I am in Tasmania so have you beat on "Southernness" by a mile.

It has gone from being highly phobic to being a pretty good place to live generally.
Rather than generalise I will be specific in the hope it means more. I am one of those who also has a trans child, and can tell you my son, living in country Victoria is accepted as just another bloke locally, and has been living with his girlfriend for nearly 5 years, so it is totally possible.
There is another Transman in the same town, Ben McEllen who has written an autobiography "A Cut Closer To Whole" and he is in a long term relationship also (Good read).
I know several girls locally here in Hobart who are in long term relationships with women also, so there are plenty of people out there who will love us for our true selves. I have even found one myself in the last day or so, so I am biased I guess.

If your family won't stand by you for something as minor as this, and place anything above their love for you they were never there in the first place, so it's their problem. You have nothing to apologise for or be ashamed of, any more than for any other medical condition.
Karen.