DCF question: I am 18 years old?

I turned 18 last year, which means I aged out of the system months ago. By the time DCF got involved with my family, I was already 17.5 years old (giving them very little to do with me). They have placed stipulations on my life, because they perceive me as a potential danger to my minor siblings. I have never been charged, let alone convicted, for any criminal behavior. Can they do this? For someone that has NEVER been in legal trouble, how can I be deemed a danger? Also, most of the incidents they believe make me a potential "threat" happened when I was three or four years old. I went to an examiner, who stated that a risk assessment was not appropriate for me.