How do I tell this girl I like her? 10 pts for best answer?

Well, I have had a crush on this girl for some time now but have only been watching her from afar. I have decided that I am going to tell her how I feel about her in the next couple of days. I was planning on going up to her after 5th period, telling her that I like her and would like to have a chance for us to get to know each other better, complement her, and give her my number. The problem is that I don't know if she will think this is creepy or sudden or something. to give some background, we are freshmen in high school, we have never talked, dont know each other at all, i know she knows my name and who I am because she knows when she pes things out in cl. what do you think i should do, girls answers would be most perferred, 10 pts for best answer, THANKS!