Marta:
You have come to the right place. And thank you so much for your support of her. You have no idea how helpful it is to have the support of your family in this process. It really can make all the difference in the world to her.
Not only do we have a large family here in the forums who are in every stage of transition. But we also have a very extensive wiki which contains a very large amount of information about transgender and transsexuality. This is a daunting process. Literally there is no part of a persons existence that isn't touched by their gender. There are legal, medical, and social implications that can be dizzying to comprehend.
Feel free to ask any questions you may have. We support each other here. And that includes you too, Marta. Your questions and concerns are important to us as well. When a person changes their gender, it is a transition not only for themselves, but everyone around them as well. It can be so confusing to everyone. Your uncle, soon to be your aunt, is going through the most trying time right now an your support will help make that time for both of you less stressful.
Thank you and welcome to Susan's!
-Sandy