About to lose hope

I just found out about a month ago that I have a half sister that was put up for adoption when she was a baby. I am now 36 and heartbroken that I didn’t know about this sooner. It was a closed adoption and I’ve been speaking with a private investigator but I don’t have enough information to proceed forward. Her birth name was Denise Violette but was obviously changed when she was adopted. She was born I believe in November 1971. She was born at Beverly Massachusetts hospital or it also could of been cable hospital in Ipswich Massachusetts. If anyone has any information it would be greatly appreciated. Thank you so much!