Sexual Abuse Support Group
Sexual abuse is a relative cultural term used to describe sexual relations and behavior between two or more parties which are considered criminally and/or morally offensive. Different types of sexual abuse involve: Non-consensual, forced physical sexual behavior such as rape, incest or sexual assault, or psychological forms of abuse, such as verbal sexual behavior or...
Have you told your mom? Are you afraid to tell her? I imagine it will be very painful for both of you if you do, but this is not something that can be swept under the rug. If you don't feel comfortable talking to your mom maybe you could start by talking to a counselor at school or a trusted teacher or other trusted adult. You should not be left to handle this on your own.
I think your stepbrother may also be very troubled by this and would benefit from talking to someone.
Please feel free to come here for support as much as you like and to let us know what happens going forward.