I'm going to have an argument with my mother.
Why are you going to argue with your mother?
We have a lot of problems between us and we're having difficulty resolving our issues.
I don't think it's a good idea to get into an argument with your mom. You should be respectful to her. If you have an issue with something she's doing you should talk to her about it calmly and politely.
My mother and I are going to therapy on the eighth, but I'm not going to speak to her during the session.
It's great that the two of you are going to therapy together to work out your differences. For the therapy to be useful, you need to speak to your mother and tell her how you feel. The therapist can help the two of you repair your relationship.