Can my mom keep my sister from me?

TL;DR: Can my mom whom I have no contact with legally prevent my baby sister from contacting me when she's old enough for social media?

I (19) was kicked out a few months ago but kept contact with my family, despite my mother being toxic and mildly abusive (she's gotten better since my childhood) and my younger sibling (17) taking my mom's side on most of not all arguments. Recently we had a major argument about insurance that escalated to my mother and I calling each other harsh names, my mother calling me a horrible child and me retorting that I learned my behavior from her since my dad, who passed away a year ago, was an angel of a parent and is where I got all my good traits from. My sibling obviously took my mom's side and their boyfriend (16) was harassing me at the same time so I blocked him, told my mother to clean up and take responsibility for her parenting choices and then maybe she can be part of my life again, ya know, putting up boundaries with her, and I told my sibling that just because I was angry at our mom didnt change the fact that I love them and my baby sister (10) (who was at summer camp when this took place) and that I would always be there for them, to which they responded that they didn't love me and proceeded to block me. I'm going to pick up the rest of my stuff tomorrow and I hope I can ease the hostility from my sibling so I can keep in contact with them and my baby sister who doesn't have social media. But if I can't make up with my sibling I'm gonna leave a note for my baby sister with my socials and tell her that I love her and she can always reach out to me when she gets socials herself. My question is does my mom have the legal authority to prevent my baby sister from contacting me when she gets social media?