Well, this was the day (or not)!
I gathered enough courage and started talking about the subject with my mom...after I started I wanted to stop and go back, but it was too late...I had to tell everything.
I started talking about how I was never a very masculine boy and how I always felt that I should be female.
It was extremely hard for me to talk to her...I started talking around the subject but couldn't exactly tell her at once...
She even got anger with me telling me to stop with the teasing.
I was talking like this was the end of the world lol but for me it is more or less the end of the world. Somehow, even knowing that being a transgender is a normal thing and knowing that I am and always have been a female inside... I still feel like a lunatic about wanting to do something like change my sex.
But then I tried to justify my condition talking about how probably I was under the effects of more estrogen when I was inside her uterus and that it made my brain to develop in a female pattern. I remembered her that I had an undescended testicle at the age of 8 yo and probably was never under the effects of as much testosterone as a boy should be. I showed my hands and told her about the 2D:4D finger ratios (mine are the same size)...
I told her that I always felt this way, but I have never put all the clues together. I told her that I have never felt sexual attraction for any girl...just the feeling of "I'd like to be that girl". She knows I am still a virgin, but she didn't know why. I told her how I always disgusted my body and how I always wanted to hide from everyone my genitals...I have never felt confortable in any locker room...
I told her how I fee a female inside and that I am seeing a therapist specialized with gender issues. I told her I am a transgender...and that people like me should go under a hormone treatment and on the future should go into a surgery to change sex.
Her reaction was much more positive than I expected. She told me that she always suspected that something was wrong with me in this matter and that it doesn't change anything. But she didn't get very well tha "changing sex" part....
After this she wanted to drink a champagne and some beers...and she ended drunk...(this is not ununsual

her depression problems always made her abuse alcohol)...and I really don't know if she understood me at all.
She started talking that she doesn't care if I am gay and if want to have sex with other men...But I told her this is not exactly what I told her...I told her I wanted to be a female.
Then she told me that being bisexual is not a terrible thing...
oh god...I told her it is not about sexual orientation at all, but it is actually about gender identification. I don't see myself as a male.
Then she misunderstood that I wanted to be a travestite and started crying...oh god

(she might be getting there, but still there is a big difference between transexual and travestite)
I think that unfortunately she got too drunk to understand me...I hope that when she gets sober again she remembers what I told her...
Anyway, I feel relieved about telling her this. It was like I took a big weight off my shoulders...but I still need to talk to her when she gets sober and see if she could accept it.