So, my sister got engaged about two weeks ago, and I just found out that she's planning the wedding for "sometime before next May." Not very specific there is she? I'm presuming that to mean a Spring wedding though, so probably sometime in or after March. Anyways.
I've been on a low dosage of HRT for about 2 weeks now and by that point will have probably been on full dose for anywhere from a couple to several months, a minimum of 9 months total since starting. Is anybody starting to see where I'm going with this?
I definitely want to wait until after Christmas before I tell my family. I've already ruined enough holidays in the past for my mom apparently, so I'm not doing that again this year if I can help it. By my estimation I should be able to hide well enough until then, unless the hormones start running rampant through my delicate body.

Anyways, I wasn't sure how/when to come out, but it looks like this event may force my hand into a more concrete timeline, so I'm trying to figure out the best way to do it and would like your input. I know every person, every family, every situation is different, but here goes.
I live over an hour away from my parents and sister. I'm close to my parents (mostly, mom more than dad anyways), and I'm not very close to my sister at all. We're amicable, we're half-siblings from my dad's first marriage aged 9 years apart, so it's not like we're peas in a pod by any means. I'm closer to my brother (also half-sibling), and he lives down the street practically. He's a "man's man" and already has questioning issues with me and my lifestyle choices (religion, earrings, choice in cars, how I mow my grass, etc...).
So, I was considering telling my sister first out of all of them, since she's the one I'm the least close to of the four. I know that the others will have to follow suit soon after though because there's no way she can keep it from her fiance or from my parents since they're all so close and like to gossip. If I tell her, it will run rampant to those three within days or less. My brother may take a bit longer to find out since he's not close with any of them but me, but they'll probably call him to find out if he knows anything about me in spite of that, since me and him are supposedly close.
My sister's even closer with my mom/dad than I am since they all live in the same city, so I felt it'd be a good litmus test to find out how she thought they'd react and how I should tell them and/or in what order, etc...
Here's the big reason for coming out though before the wedding. I feel that I should give her the option of deciding if it was OK with her for me to come to the wedding dressed as the woman I am, or if I should come as a man like everyone would be expecting. I'm really kinda excited about finding a good dress to wear, but I don't want to upstage her by coming out to everyone on
her day. Telling her though would only start the spread of information and I don't know how far/fast it would go. I feel everyone who matters should know though before I show up in a dress so they don't have heart-attacks.
Maybe I just need to wait until January and see how I feel as it's not even a pressing issue until then, in theory. I just want to do this in the most organized and considerate fashion possible, and I really want to be beautiful for her wedding.

Stupid wedding! If it weren't for that I wouldn't even be considering it right now.