searching for closer

recently I found out that my mother had recently passed .. I had not seen her since I was little .. she had a breakdown when I was young what I was told was it was do to a horrible childhood and then pretty much brushed under the rug.. My mother was adoptid I met her adoptive parents .. I think the problem came from before she was adopted she was bounced from one foster home to another at a very young age.. Looking for information on how to start looking for information on her adoption and family I was 5 years old when I met them .. I vaguely remember them .. would like to begin to put the pieces of her life together and see if I can connect with some of her adoptive siblings ,, she was born in 1938 in westboro mass .. I have been told that mass is a close adoption state.. any idears of where I can start.