This character could be an inquisitor at heart, but I am sorry to say that she is not Lawful Good or Neutral Good. A Lawful Good character is "acts as a good person is expected or required to act. She combines a commitment to oppose evil with the discipline to fight relentlessly. She tells the truth, keeps her word, helps those in need, and speaks out against injustice." So while she opposed evil, she did not act as a good person normally would, going into that barracks completely unwilling to hear their case, killed defenseless officers of that realm's law in cold blood and then mutilated their bodies. Also, a Neutral Good character "does the best that a good person can do. He is devoted to helping others. He works with kings and magistrates but does not feel beholden to them." Again, your character went in, not willing to help the situation at all except to deliver death to a lord's guard who were either minimally equipped or not equipped at all, and then desecrated their corpses, all of which is not something a character claiming your two alignments would do. To further illustrate why this character does not fit the mold of either alignment, did she cast discern lies, zone of truth, detect evil, detect thoughts or any similar spells to determine their guilt, or on the victim to ensure her story checked out? Obviously, the answer is no, as she broke the door down, gave them a false chance to tell their story while not listening at all, cut them all down indiscriminately in cold blood, and then defiled all of their corpses to set an "example".
Now let's focus on the alignments that could apply to your character:
CHAOTIC NEUTRAL: You follow only one set of rules: yours. You are free to do as you please without worrying if you are doing the right thing or not. As she was avenging a woman who was wronged, yet stepped outside the bounds of not only the law, but made it into a personal vendetta with mutilation, forgoing the tenets of honor and compassion in the process and then calling it "justice", your character best represents the freedom of Chaotic Neutral.
CHAOTIC GOOD: By taking up arms to avenge a wronged woman against the system that failed to protect her by becoming the problem, you might be able to claim Chaotic Good. You showed the traits of having a kind heart with a free spirit that is willing to fight the law. The biggest downfall to this claim is similar to the point of the Chaotic Neutral claim. However, the points of killing all of the guards indiscriminately like animals and then mutilating their corpses kind of defeats the "Good" portion, especially if your character continuously decides to continue crossing the line with indiscriminate killings in the name of "justice". However, if it is truly an isolated incident as you claim, maybe you can return to the light and truly save those who need it and punish only those who have truly earned it.
LAWFUL NEUTRAL: Your character has a near-infallible code of conduct that she holds dear. This is because law and order are what you hold dear and all are accountable to it, even yourself. Nothing is more important to you than your code, and you are willing to set aside all other ideals to see yours come to light. However, your code usually means that you are willing to cooperate with the law of the land as you wish to live in a world where all lives are governed in a way to promote order and stability. As your character has demonstrated that she is not only willing to step outside of the laws of the land by taking it into your own hands and defiling the offenders' corpses, but also slay those who are responsible for its guard instead of utilizing the law to get true justice, even if you have to go to the lord of the land themselves strongly suggests that her will is greater than any law, able to thumb her nose at it on a whim.
LAWFUL EVIL: Like Lawful Neutral, you have ideals and goals, but as Lawful Evil, it is very unlikely that heaven, hell or any other plane for that matter will be able to stop those who would see your plans ruined! You will do anything, hurt anyone, and cross any line to see your dream of a corruption free utopia...except become a part of that corruption. You will hold yourself above the fray, becoming an example to all of a pure life and use everything at your disposal to force others to see the errors of all ways except your own, as evidenced by your slaughter and mutilation of those guards who went against your will, unswayed by their feeble attempts to justify their wrongs to you. The only issue with you following this path is that the reason for you ridding the world of the corruption you see is to be the instrument that helps the innocent, not to rule them and tell them how to live their lives, you would be better suited for the flexibility of Chaotic Neutral or Chaotic Good.
I hope this helps you make your Inquisitor into the best one you can make her without holding her back with the wrong alignment and possibly deity now.