Edit: I am transitioning. See later posts. 
Hi! So obviously none of you have seen me around before because I just registered, but I've read a fair number of the posts around here, and decided to ask for some input from all of you.
I was born male, and didn't really think about my gender identity that much for years. When I was six or so I dressed up with my younger sister and walked around the house in a snow white dress (my parents had company! oops!). I also recall having dreams about being a woman, but not all that frequently.
Eventually when I hit puberty, I started getting aroused by things (no ->-bleeped-<-, right?), but all my fantasies were me as a woman, typically either doing things on my own or with another girl. It pretty much stayed like this for a while, and I just thought it was normal. Didn't really feel "wrong" in my body or anything, however. Then eventually I switched rooms with my parents, and for the first few days when I was in there, all their stuff hadn't been moved out, including my mom's clothes. Upon seeing them at night I would dress up for a while before going to bed; after a few days they just moved everything out though. Howveer, I was rather determined and would take every opportunity I was home alone or during the middle of the night and dress up. This continued for years, until eventually I was caught in shorts with my shirt off; eventually I caved and confessed to my dad, who didn't seem to approving and strongly discouraged me from doing it again. A few months later and I was completely ignoring what he said, however. This whole time I would day dream about being a woman, even thought if I could switch I would, but didn't know about HRT/SRS/transitioning, and didn't give it much thought.
About two years ago I started assuming a female persona online, and would spend more time thinking about clothes and being feminine. Still didn't really know it was possible to transition, until eventually someone informed me I could seek hormone therapy and be endowed with breasts and other such feminine features. I played around with this in my head for a while, but I decided I didn't want to do anything permanent; I think I didn't realise how complete transitions could be.
Then I ended up moving to Australia with my family (they're missionaries, it's a long story) to communal living; I stopped dressing because it just wasn't possible, and for the most part put it all out of my mind for a while. I was super stressed because I wanted to move back home, and ended up having to deal with a bunch of other issues. Once I got home, however, I started thinking about it and my gender identity more and more; for the last few years I would pray to be turned into a girl, or be able to switch back and forth, and would toy with the idea of transitioning. I would daydream about returning and seeing old friends and family as a girl a lot. When I had moved back to the US to live with my grandparents (a little over a year ago), this consumed even more of my thoughts and I eventually measured myself and bought some underwear an Victoria's Secret in Boston while I was traveling to visit friends. I messed up because I was so nervous and bought the wrong size though, and eventually got rid of it so no one would find it. Oh, and around this time I become an atheist, so no more believing god could turn me into a woman.
Fantasies, dressing, and daydreaming continued for months until I had convinced myself that once I got to college and my own apartment, I would buy a bunch of clothes and live as a woman when I was alone, but never mentally committed to fully transitioning. I also started growing my hair out; it's down to my shoulders now and nice and thick.

Then one day I ended up doing a bunch of research online and felt like I needed to do something permanent; I ended up coming out to my friend (she's a lesbian and very open minded) and deciding to see a therapist and hopefully transition when I went to college, but ended up deciding I didn't want to do that because I thought I wouldn't feminise very well and never pass.
That was about two months ago; lately it's been consuming even more and more of my thinking time, and last night I ended up deciding I probably should transition, but have been rather stressed about the whole thing in general. I have a doctor's appointment (I love my doctor, I would have no problem telling her) in a month and a half, and then basically a week afterwards I go to college. At the moment I'm a little under a month away from being eighteen, and thankfully my family has a history of maturing kinda late, so I feel like this is a really critical time to start hormone therapy. I don't really want to wait a month, but I couldn't self-med even if I thought it was a good idea, and I'm still not 100% sure if I should do it. So I ask for your input; am I just a habitual crossdresser who should continue life as a man, or should I pursue hormone therapy? I don't want to come out to my family and go back on it; ideally I only come out to my doctor and college friends and return at the end of the year much feminised; maybe returning for Christmas I can look boyish enough.
Thankfully I've been blessed with small hands and feet, and I'm not that tall. I have a fairly masculine jaw and nose, but I right now wishful thinking tells me hormones would set me straight.
So thanks for reading this behemoth post, and any input you have is desired. I live in Massachusetts for the record, and I'm going to UMass Amherst in the fall, if anyone has any resources or contacts they want to recommend.