Sexual assault

When I was 10 I had an abusive step dad and he had a 16 year old son who ended up molesting me when I told my mom she kept asking if I was sure and I started to doubt myself so I said I didn’t know so she didn’t kick him out or even call the cops Ik I should’ve said I was sure but I was 10 and since then my greatgrandma told my cousin who I’m super close with that he should never hang out with me because I like to lie about sexual assault for attention and also my other grandma has been telling him happy birthday on Facebook I told her it bothered me but she keeps going it every year Idk how to feel anymore I keep doubting if it even was sexual assault I would go into detail but I’m not sure people would like to know