Should I start Ballet?

Okay so Im just gonna throw it all out on the table here... I am 18 years old Im 5'11 and I weigh well lets just say Im not the ideal weight for a dancer Im not fat Im like 180. I started getting interested in Ballet when I was 17 I saw a poster for the Joffrey Ballet in Chicago and I just was in Love with it from there I bought my first pair of Ballet slippers and I said Im gonna lose 20 lbs before I start a class and I did now Im just hesitant the ballet school wants me to wear a Leotard and Tights and I cant wear a skirt or any sort of warm ups... I just I Love ballet I guess what my question is #1- Am I too Fat to dance? ---->a href="http://i474.photobucket.com/albums/rr109/Nhafley/Belly003.jpg" rel="nofollow"http://i474.photobucket.com/albums/rr109…/a And #2- Are there some tips for a nervouse beginner for my first time I wanna look good walking into the studio