I'm not going to write to my mom for her birthday.
Do you usually write to your mom for her birthday?
No, I can't bear with her demanding my attention over such things.
It's normal to contact our parents on their birthdays, and they'll likely be disappointed if we don't. However, if you don't have a good relationship with your mom then it's understandable that you don't want to reach out to her on her birthday. As an adult, you get to choose what level of contact you want with your family.
Nope, I don't have a good relationship with her. I have already fought with her many times over the years about so many unimportant things, so I don't want to write or call on her birthday.
You will be free of the stress now from that. Contacting her at all will bring back the power she had over you. It is time to move on with your life on everything.