I would recommend you start to let her know your not LJBF material.. Start calling her sexy.. take her out to a place where you can initiate lots of kino... tease the hell out of her... try some nlp.. get her thinking about sexual things.. make sure you can get her into isolated "intimate" situations..
The way I see it if she thinks your a friend but her panties are wet.. thats not too hard to overcome
I'm not sure how this works otherwise but i've been in the LJBF zone maybe twice.. If she hasnt told you LJBF but you think your in the LJBF zone.. you can always try to beat her to the punch tell her.. she's a good friend and tease her about being kinky... Continue to game..