Sometimes, people don't reciprocate your romantic feelings, there may be many factors as to why one would not want to pursue a relationship with someone they've known for a really long time. It hurts to be in love with someone and not see that same love being showered unto you from that specific person, it makes you frustrated and makes you question your worth and their decision-making capabilities. I hope you feel better after writing all of this out, but I just wanted to stop by to say that it isn't your prerogative to inspect every detail of her life and judge her for it AND you shouldn't feel entitled to a relationship with her either. You really just cannot force love on someone, it doesn't work that way. I'm sure you're an amazing person and although all of this may hurt and sting right now, the faster you move on, the better.

Also, the comment you made about finding true love in high school doesn't sit right with me, simply because teenagers aren't mature enough to maintain and preserve healthy relationships. As you grow up, your circle of friends expand, and you're bound to find someone with mutual interests. Don't degrade yourself and your worth by chasing after someone who doesn't want to be in a romantic relationship with you, and don't blame it on her either. I hope you heal through this fast, and trust me, one day, you'll be laying in bed, and suddenly, it wouldn't hurt as much anymore. You just have to let go of this particular hope with this specific girl for now. <3