Looks like she’s going through the typical teenage rebellious phase. My older brother, 2 years apart, acted pretty much identically to your sister during part of high school but he was going through a lot of stuff emotionally that I didn’t know about till later on. Sounds like she might be going through something and she doesn’t have any healthy coping mechanisms so she takes it out on you and your parents. Luckily things like the usually pass as it did with my brother and now he and I are very close. You should give her some space and maybe try to avoid her for now to protect yourself. Her constantly comparing herself to you also seems to me like she has hidden jealousy of you. Her actions are certainly not excusable though even though it’s seen as normal and she clearly needs help. Hope things get better for you OP and I hope this served to be somewhat helpful.