Sibling issues

This might sound a bit petty, but why on earth is it that my mom will let my sister(10) talk at full volume and play loud music at 7am while I'm(17) asleep? If it's me who's awake and my sister who's asleep during the same time period, I will be expected to hush up and stay quiet so she could "sleep better". I have a bad sleep schedule and often have to stay up for school tasks, while my sister sleeps early. Why is it that they're considerate of her, but not me??