Drawing people is a must for every person who lives and draws. That is what you did here, and should continue doing. Because you really to improve through practice.
You definitely have vision, cause I am more than familiar with the boring and the mediocre. Her expression, pose and pistol all speak to me and leave an impact.
However, on the technical side of things it is far from perfect. Her left arm is unnecessarily straight. Why would it be? It should not. Her left foot is pointing inwards. Not only that makes no sense in terms of balance, but is hard to do. No human would do that, and neither should your character.
And last, but not least, her nose is too short and too high. The lips are too high as well.
Aside from these issues, everything is fine.