HELP!!! I need relationship advice please advise?

I have been friends with this girl for a long time. She has a great personality and we always get along. She has a really pretty face but she is a tad overweight. She got stood up by this one guy and I felt like she should be taken out and treated the way a guy is supposed to treat a girl so I asked her out on a date. She was overjoyed at the idea. I was upfront with her saying I just wanted a casual date and wasn't looking to get into anything serious and she was totally fine with it. I really like her as a friend and it could possibly grow into something greater, I don't want to lead her on I'm just looking to have fun and date not put a label on ourselves. I wish she was skinner, I am a beanpole and I have cuddled with big girls before and it kinda hurts, knocks the wind out of me. Haha. I dunno what I should do, I'm being a little shallow but I want to find someone special and would never turn a girl away based on looks. Shes pretty, just a little overweight I dunno what to do, help!