Childhood sexual abuse trigger

I was taken off my parents when I was young due to sexual abuse growing up wasn't easy but when I had my first child I turned my life around studied and work everything I have done I did for them keeping them safe has always been my 100% priority my youngest is my only daughter and she is 9 yrs old her and I have a very strong bond raised her as a princess about 8 mths ago I took care of my niece 8 and my two nephews 5 & 2 it was only ever temporary til we found family for them in August we found the boys uncle (my niece has a different dad) and his wife were able to at least take the boys with the plan I keep my niece and we share care so we transitioned the boys and they moved two weeks ago last week. last week my daughter refused to play with my niece so had a conversation with about that and she says it's because she wants me to play the dirty game my niece asked her to be a bikie, climbed on my daughter pushed her vagina into my daughter and tried to kiss her my heart literally broke I told one social worker who told me it was so what they consider on the low scale, offered to send me a google link and suggested taking her to the gp the problem is I am not sure if I want to continue care the family dynamics and boundaries have changed and I honestly felt the bond I have been building with my niece for 8mths broke instantly I feel sad for my niece because I know it's not her fault and I have spent a lot of time talking & teaching her, encouraging her but I don't want to force my child to be around someone she says she feels uncomfortable with I am so stuck...sorry for the long post