I saw tons when I was little. It was probably It or one of the Child's Play movies when I was like 5. My dad refused to watch children's movies and thought we would be pussies if he didn't let us watch it. Hell, thanks to his religious nutso wife, I saw Amityville Horror when I was like 8. Then my real mom bought 1, 2 and 3 for my brother, sister and I. I distinctly remember watching the car sex scene in The Cutting Edge with my family. O.o
Now rated R movies in theater, that may have been a while because we lived in a shit town and we were like 50 miles from the theater. My first movie in the theater was Forrest Gump. I think my first rated R movie in theater was Scream. I distinctly remember it being a bigger deal that we were going to the mall alone than seeing a rated R movie.