Little Red Riding Hood's Age

Little Red Riding Hood has to deliver food to her grandma again. She can drive now because she is sixteen. One the way, she accidentally took the wrong way and got to a different forest where her grandma lives now. She found the wrong cottage that looked like her grandma's home. When she opened the door, she found her younger and older sisters of ages 9, 11, 18, and 22. How old is Little Red Riding Hood?

Answer: 16