Yes transitioning is a scary thing, mainly I think because you aren't just changing your style of dress or haircolor, you are making fundamental changes in your body and beginning to transition to a whole new gender. Having not grown up as a female does and experiencing what they experience, it is a new world that is completely unkown to you. There will always be fears and/or uncertainties concerning whether or not you can pull it off, passing, gaining acceptance in your new life, being able to survive in your new gender as far as work etc. There is a lot to consider, but that doesn't mean don't do it. It just means consider everything carefully, because if you have serious doubts they need to be addressed so that you can move forward confidently knowing you are doing the right thing.
You have my support Britney =] transition or not, that's for you to decide.