Thinking about planning the rest of your life at 14?
Wow, I was still into computer games and sports, not mortgages and other lifetime commitments!
You already demonstrate that you are an incisive thinker, well done. This is a very bad quality in WT world and you will be reprimanded for it.
My prediction if you join up in order to please everyone else and get your girl is that you will at some future point realise the mistake you made, and have to leave anyway. Doing this after joining the JW's will be far more traumatic to you both, and any family you may have by then.
If she loves you as much as you love her then wait until she decides for herself to leave the WT and join you.