I have a few thoughts on this passage. First, you do a great job bringing your character to life. You make it very easy to visualize every nervous twitch. If anything, you do that a little too well. I think the characterization youre going for is geeky and somewhat insecure. You do not, however, want her to come across as borderline dysfunctional.
There are a few technical issues that can be very easily remedied. I think Rob is right about all of the it stuff. Ive become very aware of that. Rob critiqued some of my work as well. As a result, Im currently revising 19 pages of prologue.
In addition to the IT curse, I think your wording was a bit awkward in some places. Let me give you a couple examples.
When she felt the wetness of blood she would usually stick her fingers in her pocket so the blood wouldnt show on her clothes or wipe them on an inside seam of her pants.
She took to holding her hands clasped behind her back in an at ease manner when standing and talking to someone. It was an embarrassing habit she wished she could kick.
In the first quotation, what is she wiping on the inside seam of her pants: her fingers, the blood or her clothes? Your meaning is obvious enough. The sentence just doesnt read well.
The same is true of the second quotation. What habit is she trying to kick, standing in an at ease manner? Again, your meaning is clear. The structure is just a bit awkward.
As for writing from an outline, I dont think theres anything wrong with that. I wish I had someone/something to tell me how my story would end. Ive been sort of making it up as I go along. My only suggestion is that you not be afraid to stray from the storyline youve mapped out in your head (or on paper). Some of my best writing is totally spontaneous. Unfortunately, some of my worst writing is totally spontaneous as well. Good luck with your spontaneity. I hope it serves you well.