Hi Emma,
It sounds like your sister at the meeting has some of the same qualities I see in others of her generation. Specifically, the idea that because it was hard for them then it should be hard for you.
I should expect she had to spend a lot of her life being someone else, pretending. Finally, when she knew who she was, she probably had to spend a very long time explaining it. Justifying it. She may even feel like being transgender is almost a 'club', for which the price of admission is soul-searching, justification and suffering.
Anyone who has not done those things is not really transgender and needs to shape up or find somewhere else to sling their hook.
Naturally she's mistaken, and whilst I can only sympathise with her for whatever hardships have given her a flint-like edge you are well within your rights to feel hurt. She hurt you and must take responsibility for that.
There is no admission cost, there is no minimum level of suffering or pain one must go through. Being transsexual is as much a part of us as the sheen on our eyes or the subdermal scattering of our skin.
There's an old joke that goes something like this:
Q: "How many transsexuals does it take to change a light bulb?"
A: "One. But only after they have first lived in the dark for at least two years and have the agreement of two psychiatrists that the bulb is, indeed, blown."
The lengths we have to go to 'prove' who we are can have bad effects on people. They must take responsibility for inflicting that down on to others. You don't have to prove anything, however. There is no timescale, no measure and no schedule except your own.
I'm sure the shirt and ballet shoes looked very nice and suited you well. Personally I found the first time I wore a long skirt to be almost like breathing freedom.
Kaylee.