16 year old guy and 14 year old girl?

I'm in Year 11 at school, and I am infatuated by a Year 9 girl. She's not shallow, and I'm not interested in anything besides an innocent highschool date. I've never had a girlfriend, so I don't have any prior experience and I've never talked to her. I really want to get to know her before next week. I've seen her around for the last year, but have never known how to spark a conversation with her. Her best friend is my best friend's sister, and we both play basketball at the same time. I don't know whether she likes me, but whenever I look and smile at her she looks back. She's single and I really want to make a good impression. I try to be a really nice guy by being chivalrous to everyone, and not judging anyone. I'm liked by most people due to this. I take care of my appearance and am complemented by girls in my grade, so my looks shouldn't be an issue. Problem is, I asked out one of her other friends last year (stupid mistake), and I'm guessing that she knows about it. Is there any chance that she could like me anyway? And how could I spark a conversation with her? I can't stop thinking about her, and any suggestions are much appreciated! Thanks =)