I really only had one issue with this, but that issue kept me from giving this 4 stars, because it bothered me so much.
Over-explaining. The character likes to pause and address the reader, with awkward and captain obvious style explanations. It's just unnecessary, and the story would be better without. Just show it, dude. No need to tell.
For example on the first page:
"She looked up sharply, as if - forgive me if I sound crude, it's just my style - as if someone in a distant room had farted."
That line would have been much funnier without the middle part. I mean, I still laughed (because, come on) but it would have read so much better without, you know?
So yeah. Unfortunately, it hit one of my big pet peeves with books, otherwise this would have been 4 stars fo' sho. The MC is kick ass and not fucking around. Well, she does fuck around some in another way, but you know what I mean.