I could tell you from my own life story that I have been through this. There were some girls, nice godly christian girls, that were just fine (ok, maybe they were better) and I know that in some way they were interested in me but I wasn't because as you said I wasn't head over heels for them because of my principles on dating and marriage. Now I never regret that I didn't talked and pursued them and I know for sure that I was extremely right in my way of action. Actually I've never had any relationship with a girl due to the fact that I'm kind of one-man-woman but I don't regret this because now I'm receiving the blessings for this (am about to get married).
But what I want to say to you is to give a try so that you don't have to live with the idea in your mind "what if". If you still have a chance to do something I for one if I were in your boots I would start praying, fasting and reading my Bible and asking willingly God to guide me through his Holy Spirit giving me discernment to do his will and ALSO I would talk with my parents and siblings (this worked for me so many times) and WITH your pastor or mentor because this way you would receive some very good godly and practical insights. And after that, after you take advise from them you act in a way or another. You can do this just this very week but don't loose your patience man. Even if you don't succeed you will see that with time these feelings of yours will pass and you will be fine.
So, what I'm saying to you is to talk with some more mature persons closer to you and you will see what you have to do. But beware whatever decision you will make you will suffer the consequencens of your choice so beware to follow God's leading and take seriously into consideration the pieces of advise you receive. Good bless you and I trully hope you that maybe this girl will be for you
. If it would be would you gave shout out
?