What you are experiencing is hormonal longing based on little else than secretions in your brain. The idea that you saw some girl and went mad about her doesn't say much about your rationality. Instead of hunting down anti-JW's for Dear Abby advice, you would be better off dealing directly with your own value system. It is in need of recalibration!
Are you thinking about what is best for you, or, her? It would be highly destructive to this girl's family security and her own valuation of her personal relationship with the Supreme Being in the universe to fall into your clutches. Why would you wish that on somebody you claim you have feelings for?
Ever hear the song: "You can't always get what you want..."?
Sometimes with certain people it is the challenge of being forbidden access that drives their hormonal ambitions. Mature a little first, develop a philosophy of life that transcends your physical urgings and fantasy longings and construct a purpose in life.
Don't go to strangers and ask for advice. We don't know you. We don't know her. We only know we have been badly misused by the same religious organization that this object of your affections is affilliated with.
Read a book, exercise and build a life for yourself that excludes young girls in a mind-control group. You'll be glad you did.
T.