Welcome to your teen years.
Crushes come and go and yeah, they hurt like hell when they're happening. Fortunately, they don't last forever. And sexuality confusion happens, too. Sometimes it sorts out one way, sometimes another. So be it.
Her wanting to go slow is one thing, but don't let everything go so slowly it grinds your life to a halt. That is, don't wait for her to make up her mind. Live your life. Your awesome, fun, smart, kind, terrific life.
This life can and should contain other girls, and maybe other relationships. There's nothing wrong with that whatsoever.
If she's interested, and she wants to date a guy, she'll come around. Having an interesting life will make you that much more attractive (there's nothing more awesome than someone whose **** is in gear -- trust me on this one), to her and to anyone else.
Have such an awesome life that a relationship with her or anyone else is the icing on the cake but not the whole meal.