Okay, I already see TWO 'how-do-I-tell-my-parents' topics, and I bet this question has been asked a BAZILLION times and is nearly impossible to answer, so I feel kinda reluctant to post mine.
But as of lately I'm getting REALLY frustrated with my physical body, the way people adress me, etc. In the past years, there always has been something that could 'distract' me from my dysphoria. Either it were my classmates, bullying, being excluded from the group, or school/work pressure, or both. Deep down I always knew I was trans, but I always fled into those other problems so I didn't have to face it. Later, in college (for half a year, lol!), I knew of myself I was trans, but was still a bit doubtful and VERY VERY scared, so I did it again. I told myself those other problems (like exams and feelings that I wanted to pursuit another career/study) were way more important than the 'transgender business', and put all my energy and focus on those instead.
Now I am having like half a year of holiday, not having a job, and a depressed and over-worrying mother (when I was little she worried for me, now she worries for herself and constantly feels like she 'doesn't belong with us' even though we ( = me and my dad) try to engage her in stuff really a lot. She does nothing all day but lie on the sofa and worry about her health, her life, everything. We tried to motivate her to do stuff, no avail, we got her to a psych, but all she does is complain it doesn't work and it makes her tired. Both me and my dad are going crazy from her!).
In the meantime my social anxiety and dysphoria are getting much worse, and I have no-where to flee to (for the better, probably). So I feel like I really HAVE to tell my parents. But I am 1) SCARED TO FCKING DEATH! and 2) worried my mom might not be able to take it (but I don't think she'll get 'better' within now and, say, a year)
So, okay, my mom won't get better in the time being, so I can best just come out to here asap anyway. It can go in two directions, either she cannot accept it and freaks out even more than she used to, and her mental state will worsen even more, OR her motherly love for me and desire for me to be happy is strong enough to let her accept it, and my troubles take her out of her ego-bubble-of-self-pity for a moment, and she'll focus all her negative and worry-energy on helping me, maybe even becoming an advocate for transpeople. How weird it might sound, both options are very much possible. But either way, it doesn't matter, because he situation right doesn't seem to improve anytime soon.
And then we have No 1... my freaking fear!

Maybe the hardest to overcome. I am not a courageous person, but I never thought I was a real coward either, but now... I am doubting that. I have seriously NEVER been so scared before, and I don't even really know why! So many people come out, so many transpeople have walked this path before me, and succeeded. If they can do it, I should be able to do it too, right? But whenever I try, my stomach constricts into a tiny ball, and I feel like I'm going to pass out or vomit or both. Usually combined with crazy sweating, trembling, and loss of words. Farthest I came was like "Mom, dad, I gotto tell you something... *wave of fear passes* ... uhmmmm nevermind... what's for dinner?" :x
I even don't dare to just plain TALK about transpeople in general. Crap man! What is wrong with me! How can I GET MYSELF TOGETHER!? I have never felt such a goddamn coward before :s
(oh and sorry for the rant, I just had to let this out for a sec...)