Do Grades Matter?

Hello! I am currently pursuing my EdD. I have always been someone who strived to achieve all As and came very close in my ADN and did achieve it in my BSN and MSN. I am now pursuing an EdD. I need to maintain a 3.0 GPA and obtain a B or better to pass my classes. Beyond that - do grades matter now? Is there a difference between an A or a B at this stage? Or will it only matter that I graduated and what my research/dissertation is? Obviously I will do my best work regardless but relieving some of the stress surrounding not getting that "perfect grade" will help my mental status if someone can convince me it won't matter at the end of the day if I get a 3.0, 3.5, or 4.0.