I thought I said no

Our parents were out    
You said it was a surprise    
   
So I followed to your room    
Where you grabbed me from behind    
   
You were sixteen    
I was only nine    
   
You told me to take off my clothes    
As you locked the door    
   
There was no way I could stop you    
So I laid there petrified    
   
I tried to say no    
I tried to defy    
   
But you thrust into my body    
And I let out a scream    
   
And when I tried to run away    
You growled and pulled me close    
   
You took a tie and wrapped it    
around my mouth    
   
Same for my arms and legs    
So I couldn't run away    
   
Hours later you told me not to say anything    
Or you'll hurt me again    
   
So I sat crying wondering    
What I did wrong    
   
Why did you do it    
I thought I said no