A Lilley (or Lilly) is someone who is too beautiful, athletic, really smart, and funny.
Basically everyone loves her and wants to hang out with her. Tons of guys are in love with her and are amazed by her smart comments. She is fun to hang around and filled with sunshine. Creative and out-going and craves to be where the fun is. Isn't shy and likes to be on stage.
Dude, your girl is such a lilley :P