I’m am so incredibly sorry and hurt for you. I’ve had a friend who once said “just speak normally” and that’s when I became self-conscious of how I spoke at 11 years old. I am also 18 and am still navigating the dark hole that is stuttering, but Please, Please don’t listen to them. Stuttering is not something that defines you and is such a small thing. (Even when some times we feel like it surrounds everything). And honestly who cares that you stutter. And if your sister does, it’s because she would rather focus on what she appears as your “flaws” instead of facing her own demons. If there is atleast one person in your family who understands, please talk to them. You are awesome no matter what.