You came home to find your younger sibling in your room, going through your things — reading the notebook where you write stuff you don't show anyone. They weren't being sneaky, exactly; they just wandered in, curious, and helped themselves. Now they know things you never wanted shared. You feel exposed, furious, and weirdly ashamed, even though you did nothing wrong. When you tell your parents, they say "it's not a big deal, they're just little." But it is a big deal to you. You want a lock, a boundary, a guarantee — and you're not sure you're allowed to ask for one.