Perhaps the more important question is why your mother doesn’t respect your personal choice about the issue, nor accept as sufficient the explanation you give her, nor try to understand nor accept your personal feelings about it. It sounds to me like there is something more fundamental going on in your relationship with your mother, which has nothing to do with ADhD, such as her propensity to control how you feel or what you choose to do, or not do. Just an observation.
JH