Son compartido

AITAH for laughing when my little sister walked in on my parents My little sister, 12F, came into my room in a panic claiming that she couldn't find our parents (it is 11 pm). For context I am 16F. She said that she could see movement in our dad's van and that she was gonna go and check it out. I, knowing what she might find told her not to, but she didn't listen and I was barely awake so I just told her to go back to bed (I figured she'd just look out the front door and go back to bed). Five m