Wall of text. I really would appreciate it if someone could help me with my situation.

Here is my situation. There is this girl that I liked since September. She is a senior and I am a junior. I never had the chance to ask her out, because someone asked her out in October. I waited so that is what I got. I was really in to her and when she got asked out, it hit me really hard. She was the first person that I ever felt this strongly about. After some time, I thought that it was just infatuation or something so I kinda got over her. However, while she dated that guy, we became even closer friends and shared really intimate stuff. I started to like her a whole lot more than I did back in September. She just broke up with that guy one month ago, and my chance was right in front of me. I then remebered that prom was rolling around, and I wouldn't be able to go to it cause my parents are really anal about relationships. They don't want me hanging around girls because of a strange, yet plausible reason. The story pretty much is that my dad's previous person didn't want him to study, but she wanted him to make money for her. Anyway, he thinks that I might get used or get into a bad situation (premarital sex). I was planning on asking her out after prom (May) because I get my license then, and being with her would be easier. However, the ex came back into the picture starting 1 week ago and started to hang out with her again. I mean,he went to her house at 11 pm just to "chill" for an hour. He is always around her at school, and it seems like he isnt giving up. I really would like to talk with her, but he is always there, and if I tried to sit down with them,it would only be awkward. Also, my "depression" is starting tokick back in just cause they are spending soo much time together. Oh one more thing, today, she was supposed to come over so that we could study for a class, but that guy asked to go to her house for her mom to tutor him in math so she won't be coming over...I amr eally sad and I don't know how to address the situation. Thanks for whoever read that all. I would really appreciate some help.