You are not alone, Zoe. For me, it's because Robin has been hidden all her life and is demanding to get out and take part in the world. Apparently I resent having hidden for nearly forty years. It's discouraging sometimes; currently I'm full time at home (even when dressed male, my fiancee and her kids call me Robin and use feminine pronouns, even when I'm not feeling feminine at all. They're wonderful, really.

) I do work in an extremely conservative place, though, as a software developer. I am out to my immediate supervisor (coincidentally the guy who cuts my checks), but as a contractor (who can be fired at-will) I have to work in guy-mode.
I'm pre-HRT, only had my first electro appointment yesterday, but I'm going out on the town and out to nearly everyone, including my mother. This is all in a period of about two months since I finally came out to myself. Granted, I had been calling myself gender-queer before as I eased my way out of denial, so that gave me a *bit* of a head start.
Anyway, all this is to say that I understand where you are coming from. Sometimes I want to scream in fear at the whirlwind of change, and others I want to scream in hurt and anger about ever having to present myself in "boy mode". It's a wild ride, believe me. *hug*
It sounds like you're taking sane steps. As others have said, wardrobe takes time and money to put together, as do your makeup kit and accessories. And I can pretty much guarantee there will be down days where you don't want to dress at all and just hide out in your room. Sometimes when you ride an intense ride at the amusement park, you need a break before you get back on... be sure to allow yourself some breaks, some time for reflection when you feel you need them.
*hug*
I'm excited for you!