You have a step-brother that very protective over you. He never allow anything and you should get permission to him for everything. Your mom knows that but she didn't say anything. You need to live like this and you live for 3 years.

Now he find out you drive motorcycle with his friends and he going crazy.

He grab me from my neck and force me to look at him. "If i see you with my friends again, i will make you regret. Did you understand, my little sister?"