The anger is caused by repressing resentment and hate.
If you are sincere with a desire to forgive, your anger will cease.
but you must be sincere.
I was very angry, I held hate towards my mother, when I realized she hated her mother and others, who hurt her, I saw she could not help herself so it was easy to forgive. I no longer repressed hate that was ruining my emotions.
Anger is caused by resentment and hate and hurts only ourselves.
You desire to change is beautifu.

Hope this helps,