Should I ask her out?

I really really like this girl. She is in all of my good subjects (option classes) I am in year 8 and so is she. Last term she kept asking and begging me to know who i liked and I didnt tell her that i liked her. And in drama we were told to go into pairs to work on a script and to practise and performmit. We got top marks both being very confident people and it was fun. and in second term she kept asking again and my friend who didn't know that i liked her said Oh it'll be funny if it was you and I just laughed and he said omg u do like her don't u and I smiled again and she blushed. She gave me her msn and asked what I liked about her and unsaid oh your so Pretty and smart and got a great personality. But then she teased me saying she liked someone else and made me guess until I got it right and the guy im up against I really dislike for starters and he dOsnt get along with me either. And he didn't know she likes him. But when he went out with someone else at school she was crying and really upset. She's better now after 3 days and in drama were doing a class performance and she in the play is my girlfriend and in it I propose to her and she has to reject me cos I'm a commoner and she's a princess. I don't know what to do or say to her should I ask her out or just remain friends. I really REALLY like her