It can be so, so frustrating when our children are rebellious or argumentative. We can tell them one thing and they will argue the exact opposite just to disagree! Your daughter is also at that age when life becomes more difficult: Puberty and hormones are raging, her body is changing, things feel more emotional, moodiness and irritability are common, social issues become more pressured, self-esteem is more fragile, insecurities are rampant, academics at school become more challenging, and on and on.
One thing you may do is sit down with your daughter when she is open and in a good mood and just talk openly with her about the behavioral problems. What are your main concerns? The stealing? The argumentativeness? What does she see as the problems? Narrow it down to one or two. Have her participate in the solution.
A reward system is a great idea! Maybe your daughter will hook into the idea if she helps come up with the plan. Reward small steps. If arguing is frequent, it may be hard for her to go a whole day with no incidents. Break up the day into chunks and reward small accomplishments.
If she argues, don’t get pulled into a power struggle with her. If you have told her “no” and she wants to argue, don’t participate. Calmly restate that you have said “no” and walk away. Go to another part of the house.
Be consistent in the way you respond to her. If you have told her “no,” stick with it and don’t give in. Be firm, but matter of fact.
Catch her when she is being good and praise her. Children, especially those with ADHD, often hear only the negative. It is so important for them to hear what they are doing well! This positive feedback is very powerful.
Try to plan regular one-on-one time with your daughter when just the two of you can be together. During this special time be there for your daughter to listen and be a supportive presence for her. You may find that she begins to open up more and more about her feelings.
If you are still feeling that some of her issues may be ADHD-related, search around your area to find professionals experienced in treating ADHD...even better if they have experience treating girls with ADHD. It may or may not be that she has ADHD, but if she is seen by someone who specializes in evaluating, diagnosing, and treating ADHD, you can feel more confident in their assessment. Once you have more clarity on this, you can proceed with appropriate treatment.