Am I wrong for this? Please read

Backstory: My three sisters father (my stepdad) raped me from ages 5-10 and is in prison for life. I had told my mom the first time it happened when I was 5 and she told me not to say stuff like that because the police would come take all of us away... fast forwarding to 10yrs old and I told her again and she realized I knew it was wrong and was old enough to take action so finally brought me to the hospital and claimed to had not known it was happening. From that day my grandparents took me and my sisters in and still have custody of the youngest (we’re all 18+ now). My mother has been couch hopping from friend to friend is even started doing meth among other things in the past 5 years. She even dated a registered sex offender not even a year after my stepdad was sentenced and tried to bring him around my sisters and I.

Well I’m pregnant and have not and continue to not want anything to do with her. My Grammy (my moms mother) says I’m selfish and a liar and there’s no way her precious daughter knew all that was going on and doesn’t do drugs (even though she admitted she knew and does do drugs). I have blocked her on fb and my Grammy and all that side of the family because I don’t want them to have anything to do with my child and don’t trust her for a second. Not to mention she always brings her meth head bf around who stole from my grandpa(my sisters dads dad) and pawned his stuff and his wife’s (my now dead grandmas) things.

My Grammy says I need to forgive her and let go of the past but I can’t. I hate her so much for allowing me to be hurt and having to watch over my sisters to make sure he didn’t hurt them.

Am I wrong for not forgiving her, not wanting anything to do with her? She constantly messages me and apologizes but I don’t believe her and hate her for ignoring me after telling her I was being raped.

These are screenshots from her. She visits with my sisters once every few months so found out I was pregnant from them.