This topic is very interesting. When the gal calls you dai, there is nothing wrong with that but NEVER call them Baini ke cha.instead, call them by their name, pooja, pinky, sandhya manddya... etc... If you are not from the same class back in school, likelyhood is they would call you dai coz you might be senior in education and age. If you are not related by blood to her, its not sin or anything to like her on that way... Some senior girls here in sajha told me that they call some guys "dai" but don't like to be called "sister". So that, guys feel it, no matter whether that gal called you dai or not, still she can build up feelings for you.. I have seen so many nepali girls calling dai and falling in love to that dai.. (happened this with my friend/cousin) I have seen a girl calling my best friend dai in public but they were real lovebirds in the house.(happened with my best friend). One girl used to call me dai, when my cousin proposed her, she told him that she likes his cousin( happened to me) . worst thing, i did not like her that way though. She still call me dai but i never called her baini. About the age, it's not bad to like younger girls by 8-9 years difference... I have asked to few girls and they don't mind for it. Some does though.. If you happen to like very young girl, there is chance to break up soon. thats wat I have seen around. So that gamble on your own risk brothers. Amen!