Hey OP - I get it. I had a similar situation in my early/mid-teens. My sister was two years older and one of the more popular girls in high school (I was on the other end of the social scale) and I had a much younger brother. I loathed my stutter and the fact that four-year olds were more fluent than I was. I wanted to pretend I didn't stutter and I generally didn't around my immediate family. I was so self-conscious about the "silly" sounds I was making during the exercises and I was so concerned that one of my sister's friends would hear me and blab to the other cool kids who would tease me (thankfully this didn't happen), and I also didn't want my brother to hear me in case it changed his views of me (I liked to think he looked up to me). Everyone's stutter affects them differently and everyone has a unique and deeply-personal relationship with their stutter - truthfully, I've accepted my stutter, but I still won't do any exercises if I know my wife (we've been together 15 years) or my kids are around (the shower and while driving for me). It's just a personal preference. I would politely ask your mum to trust you to do the exercises and that you are serious about your speech or to send you a text reminder in the future. You could explain how your stutter makes you feel and that sometimes you just don't want to be reminded in front of everyone that you are different and have a sometimes-embarrassing stutter.