I need a girls advice?

there's this girl that I have always found amazingly attractive but the thing is that I really never gotten the chance to speak with her and now is the only time I get to see her because we're rehearsing for our graduation ceremony. Since we only got two days left of rehearsal I was considering of just being straight forward, confessing and honestly telling her that i think she's cute and ask her for her number but the problem with that is that she's my partner and in case she ends up saying no i don't want to make her feel uncomfortable on her graduation day when I walk towards her, give her the rose (which is part of the graduation ceremony) then walk down the aisle with her. I don't really mind taking the risk and asking her but I don't really want to�embarrass�her in front of her friends and make her feel uncomfortable on her special day either. What do you girls think I should do? Should I just forget about her or should I try and take the risk? Also if you girls know of a way and think there's a different way I should approach her can you please tell me? that would help me out a lot, thanks!.... Lol Sorry if it seem long