I went through this exact problem right before going full-time, and I can pretty definitively say that it was nothing but fear of the unknown.
Unless you're starting to have doubts based on thinking that you'd rather be a guy than a girl, and not just on "I can't picture it," you have nothing to worry about. I still honestly can't see myself as a woman internally on a lot of days, and yet I'm full-time and loving it! So even though my own mind is still working on the self-acceptace part of it, (I've heard that it usually takes 6 months of full-time or so for your mind to really adjust to getting used to seeing yourself as actually being a member of your identity gender,) I still end up going out as a girl every single day, not being the least bit remorseful, and being pretty damned happy. And I'm still miserable every time I think I'm seeing a guy in the mirror, and ecstatic when I see a woman in the mirror.
So yeah... are you doubting that you want to see a woman in the mirror? Are you doubting that you want to have a female body? When you see a guy in the mirror, does it still bother you? If that's the case, again, don't worry. It's just your mind re-adjusting after a lifetime of being used to seeing yourself as male. And pretty much everyone probably has one of those "OMG, this is REAL.
ME? Actually a
woman?" moments.
