Possible interfaith relationship, help please! What should I do?

I am a devout Christian guy and I have had an on and off crush on this Muslim girl for almost 2 years. She is extremely sweet, one of the nicest people I have ever met. We are friends and I really enjoy talking to her, every time after I talk to her I feel refreshed and energized. I couldn't get get out of my head so I went out with another girl who I kinda liked, but not too much, we went out for 10 weeks and broke up, never did anything more than hug. That however failed at getting her out of my head and still really care about her. I really have no idea what to do on this. May I please have some advice?