Not a child, Not yet a woman

Ok , so i wake up a couple mornings ago and i realize I am not a little kid anymore . I am 18 now and Im grown ,Well to an extent. I still can't bring myself to look at an adult and argue with them (some kids my age don't have that discretion ). But in the same thought ,It came across to me that in the eyes of the adults in my life Im still a child. Uncle's,Aunt's ,Older Cousins.

So where is the line ?
Am I an adult or am I a child ?

Just dont know Anymore ,I thought I did but i dont