It's verbal and emotional abuse. I wouldn't quite call it sexual abuse, although it does have sexual overtones. I could be wrong, but I define sexual abuse as using someone for the abuser's pleasure who doesn't have the capacity to consent. Child, persom who is disabled, etc.

It sounds to me like your mother feels threatened in some way and doesn't want you to outshine her. She may think she's getting older and isn't as attractive anymore. So she undermines your confidence and makes fun of you so she can feel like she's still the queen bee.

Just a guess, of course.