I have some questions about someone who used to go to school with me...?

Euh I don't think you should even care about this situation. Just because you heard stories and rumours about her with other people, does not necessarily make them true. It's time to move on and you will meet others, maybe others who are even better. Liking her is just a phase, and you will eventually overcome it. Due to lack of details, I am not sure whether she likes you or speaks to you, but it sounds as if you haven't spoken with her. You can always give it a shot and speak with her, but don't be surprised if you face rejection. It's junior year of high school and I hate to say it, but you should be focused on your studies, rather than a "sluttly" girl. As a girl, girls just want to fool around in high school and no one is looking for a serious relationship. It's natural to have an attraction to someone, but you should also try to wait to see others too.