hey!!!
It seem we have similar story, I am 28 but I realised I was transsexual at 27. I've never felt the need to cross-dress when I was younger, I wanted to look more masculine when I was a teenager as well. I never really felt dysphoria either at least I never realise it at the time and considering that my dysphoria is pretty mild that could explain it. I've doubt my sexuality somewhat but I like to consider it as evolving, the more I mature the easier it was to keep an open mind and it made me go from hetero to bisexual and finally pansexual homo-romantic. All that about being passive and a push over too.
On the other hand I do not have OCD or Anxiety, I want boobs and SRS.
Now the fun part: "How did I realise I was transsexual?". First of I had a lot of fetish when I start exploring my sexuality and it evolve to the point that in the last few years I could never see myself as a guy in any kind of relationship. While at the time I found it odd, I just let it be as some kind of new fetish of mine. I played a lot of mmo in the last 4 years, while at the start I could not conceive of having anything but a male avatar but at some point I did try to make a female one and since then it simply feel wrong to play as a male at all. At the same time I start to make friend online whom I told I was a woman which at first was suppose to be a joke but the more I was refer as a woman the better it made me feel, it made me feel free to talk about anything without having to censure myself.
Finally after all those hints(there is a lot more I just don't want to write a book here

) what made me really look up transgender was my interest in Kristen Stewart and 3 of her movies(The Runaways, Cloud of Sils Maria and Still Alice)
plus some interview I saw of her made me relate to her so much that it just made complete sense to me at the time.
Any doubt I have now as nothing to do with being a trans woman but all about the trouble it could cause me and my family.
After that I've been going over everything in my life till now to see if there was any indication of this. I've realise that all my life I try to fit in with everyone else, that all my decisions up to now were made to follow the social norm or to please others. It was quite the shock really and it something you really should ask yourself "Why did I really made this or that choices?".
Apart from that Dena made really great comment in her last 2 posts here you really should follow all her advise I'm certain it would help you.
Hugs

Émily