Answer:
Dear Mom,
I understand why you're so concerned about me. I know that you worry because you care and I appreciate that.
I'm doing my best to make good decisions and I'm trying to stay out of trouble. I know I made some mistakes in the past but I'm trying to learn from them and be better.
I want to make you proud and I'm doing my best to stay on the right path.
Thank you for always being there for me and for believing in me.
Love,
Shane