If you do not want to tell her about your sexaulity as you feel as though she will tell everybody than that is your right/choice in life but until than if no decisions have been made the simplest thing to do is to not lead her on but say if she'd like to be friends and invite her into town or somthing unless you don't want that either. Don't be blunt about it next time it comes up FROM HER if it does which it most likely won't just say somthing like "I just don't want a relationship I don't think i'd be able to handle it well" than follow it up with like but we can go to the movies as friends if you'd like but if you don't want to be nice which is fine just leave the movies out.