How Can I Be a Classy Lady?

I'm a 16 year old girl and I want to be ladylike, lovely, and elegant...like Audrey Hepburn or Grace Kelly, but I am just so impulsive and hyper that I come across as wild and immature. I have always been this way, and I'm always getting made fun of by my family and people sometimes don't take me seriously. I'm just so quirky, and imperfect. I'm just so sick of being a joke and a clown and the "funny girl." I really don't mean to be and on the inside I am just a girl who wants to live in to 50s and wear dresses and be classy, I just don't come across like it. I guess I just try to be funny in front of my friends that I end up making a fool of myself, or I'll take a joke to far and end up making myself look bad or hurting someone's feelings unintentionally. I just can't be quiet, I can't stand still...I'm a wild thing, but I don't want to be. I'm not asking for advise of how to look like a lady because I know how to dress like one and I'm not saying that I'm pretty, but I'm not ugly either. Basically, I look and dress like a lady, but I don't talk or act like one. I have ADHD, so that makes it hard for me too. I guess I just want to be someone/something that I'm not no matter how hard I try. I'm just so energetic 24/7. Does anyone have any ideas on how I can channel my energy to be vivacious and classy not hyper and immature. I just want to be a lady so bad, I just don't know how to be it. I don't want to be socially awkward or repulse people, I just want to be classy and ladylike. I just say things that I don't mean and words just spill out of my mouth before I can think about what I am saying. It's just so unattractive, and my parents are ashamed of me. Please help me!!!