Hi, I have been very worried about my sister. Seems like all she thinks about is the boyfriend and doesn't even talk to my mom or dad about anything.
My dad tried to talk to her about school but she just tells them to go away.
Seems like all she cares is about the boyfriend.

One time she lied to my parents about going to one of her girlfriends party but she was really going to the boyfriends party to meet him or do what ever. But she lied to my mom and dad and I'm really worried she might gain some kind of habit in lying. I think her hormones is growing too rapidly.

She lied about going meetings for her student council.
She lied about going to a study group on her friends house but really went to go to the mall with a bunch of her friends.
Today she just tooked off to go to the mall without even getting my mom or dads permission if they would allow her to go.

Every time I tried to talk to her like this
"hey you gotta stop lying to mama, they know your lying all the time and it really hurts their feelings."
She answers back;
"f*$k leave me alone,"

Please show me a way I can help my sister and not ruin me and her relationship.

Tell your parents to start grounding her, and punishing her more often, she will eventually learn, your parents should keep a CLOSE eye on her.