Bravery or Craziness?

Let me tell you a short little tale in which I am viewed as a villain. However, I should be considered a blinkin' hero, I could have died if the circumstances would have been different. Let me begin the yarn.....
It was an innocent enough night. I was at the very computer from which this story is being written from, playing some sorta video game. Mom was on the couch nearest to the TV, her back to the three windows that grace the outer wall. The babies were asleep, and papa was in the shower. Derek was sleeping and the girls weren't home, I think they were gone somewheres on a trip. And what was I doing up so late? I was merely playing a game, I mean those things are addicting. Anyways, I was up and that is all that matters.
As I was gazing in a sorta comatose at the screen of the computer when I saw a flicker of light reflect off the screen. Since I was in a trance it didn't dawn on me that it was lights from outside, not inside. I slowly turned around and calmly asked my mom if she had been expecting anyone. Mom promptly said no, and then a little warning flare shot up in my mind. I ran to the kitchen window and saw headlights shining on the shop doors. I told mom and she thought that maybe people were robbing us of all our tools and she told me to do something. I didn't know what to do, I'm a scrawny little nerd! But I ran downstairs and went straight to the gun safe thingy, and grabbed the Ruger. I then went over my mental plan in my head as I vaulted up the stairs.
OK, I am going to unlock the door and slip outside unknown to the thief's. I will then creep up behind the woodpile and take a gander at whats going down. If I see them stealing tools, I will take a warning shot in front of the vehicle and bellow at them to drop everything. If one of them makes a move to run I'll....
I didn't get any farther, because the moment of truth came. I unbolted the door and, with my right hand squeezing the gun, I stepped out. Then I saw two people walking towards the house! I fumbled with the gun, and backstepped into the doorway. The two people looked up and froze at the foot of our porch, and we locked eyes in a silent showdown.
Now it didn't dawn on me that these two fiends were actually my sisters. I was going to capture the robber, that's all there was to it. Only when Rachel managed a nervous "Hi" that I snapped into reality once again. I looked at them, then at my gun, back at them, and then grinned sheepishly. I don't think I'll ever live that one down, me nearly shooting my sisters and all. And on top of this, mom claims she didn't tell me to go outside! The nerve, just cuz she doesn't want to get blamed with me. Shameful of her, making me take the fall for her mistake. And now I just realized that she'll be reading this and shaking with anger, not mirth. So i better leave before I say something I regret.
However, I stick to my story of untold courage and valour, as I could have been hurt or killed if they were robber. Depends on how much they want that power saw.............