Like many in the reviews said, the plot setting was quite unnerving involving the underaged boy. If we look beyond the surface, I think this particular setting is to symbolize the social norms against anyone's desire in life, not exactly on sexual life. The protagonist faces all sorts of judgments from friends, family and society as a whole on her choice of marriage, job, etc. I think the directors use a very controversial love story to set the tone, as a vehicle to show how heavy the pressure could be on anyone. A lot of time, one may not even realize that one is yielding to the social norm because we've accepted it as, well, normal.
If we view this series from this angel, the plot becomes easy to understand. And the story unfolds very beautifully and the acting is superb.