May I know the age of the girl? I might be not expert in this kind of thing, but I do think that you need to tell the girl about your feeling first :D Because I'm not really sure If the girl can wait until 6 years without knowing your feeling. A girl is a girl, and if your girl is Acehnese, after graduating people around her will start to ask the question about marriage, especially the parents. If she hasn't got any of the "calon" yet, they might start to help her search for one.