Family fraud please help!!?

I am a 18 year old female. Two years ago my mother died. I now stay with an older cousin and her three daughters. I recieve money from the government on a monthly basis. one from social security because of my mothers death and one from child support because my father owes about twelve years worth of back child support. for the two years i have resided here i have not recieved any of the money and none of it has been used for my wellbeing. my law teacher says that at the point that i turned 18 the money should have been turned over to me. is this true? if so what should i do? i really need this money to help me prepare for college.