My Secret Life

This is a three page story i did for english, if it sounds good i'm thinking of extending the plot to fit a longer chapertized book, but id like feedback.

It's about this girl named Elise who is secretly a assassin for the government, her childhood enemy comes back into her life after a couple years of freedom, after leading a group of thugs right to her family, she has to try and protect them from danger, and risk her secret coming out.

A little bit of the book >>>
'Why am I so stupid?! How could I lead them right to my family?' I paced frantically around my room, over thinking everything. I should have been more careful, put more thought into my actions. I should have parked further away. UGGH!!!!! What's the point in even thinking about it, its over and done with already. I threw a book at the wall, smashing a dent above my vanity. Damn...now i have another thing to fix, just GREAT!

'Yesterday everything was completely fine, i went to school, kept my head down, and blended in. Now i'm pretty sure my family is going to be murdered', I muttered aloud. My mind kept thinking, not giving me break to get a deep breath, and think up a fool proof plan. I was interrupted by a muffled noise outside my window. I pulled my knife from under my bed. Sliding over the wall next to my window, i peered around the corner.