How can I convince my girlfriend, she's attractive?

Not only that, she's created this insane persona that she puts on for people because she was teased in middle school! I've seen right through her from the start but in the past two weeks I've discovered things about her that her mom doesn't even know! She's an Anime addict, she's an AMAZING singer, she loves the movie When Harry Met Sally(Legendary!), she's a total perv like you have no idea and my god, I just love everything about this girl! She pretends that she's some innocent moron around most other people to cover up that fact that she's a pretty well rounded and well educated individual. I have NO IDEA how to get her out of this spiral. She's convinced herself that she's plain, ugly, boring, annoying, and that people will hate her if she shows her real self. The reality is that people dislike her now because she acts like such a prude! Back in Middle school I guess she was kinda chubby( I didn't know her ), but now she's Absolutely gorgeous! She's a 10! Cute face, slim waist, pert butt, big chest, pretty hair, luscious lips, beautiful eyes and a voice of the gods! But because of her past humiliation, she's so reserved around other people! I'm the first person she's opened up to mentally/emotionally and physically in her life! We're both in high school. I'm a junior and she's a freshman. We just started dating a week ago. How con I possibly help her to show her true self to people and to see in her what I do?