Old wounds never heal

I was assaulted by my nephews dad. I was 14/15 and he was 24. He had been living at our house for about 2 months after my nephew was born. He was supposed to be taking me Go karting for my 15th birthday but instead . . . you get the picture.

My sister has always blamed me because I the 14 'flirted' with him. My parents didn't press charges because they didn't want to upset my sister. Ever since I've always been told to suck it up for my nephew . . . always. Its always been about saving my sisters feelings. Don't have any emotions. Why are you getting so mad?! Just suck it up because you love your nephew.

Fastfoward 18 years. My nephew graduates high school this year. The date is the anniversary of the assult. She asked me if I had a problem with the party being at his other grandparents house (part of the assult happened here). I told her yes. She said she would look for another place to have the party. But she has since told my mom that I always suck it up for my nephew so shes just going to have it at the house.

Why did she even bother to ask me if she was just going to do whatever she wanted . . . it's taken a lot of years to be in a good place and I'm worried this is going to open a lot of old wounds. I obviously love my nephew. It's not his fault but I feel like this is a lot for my sister to ask of me and I don't know what to do.