Hi all😛, okay I have a theory on what Vidya's secret might be. Here it is, let me know what you think.
Vidya comes from a very small town that is very very traditional. I'm thinking that maybe Vidya was married when she was young (child marriage) and her husband died. She might be what they call a bal-vidva (child-widow) I came up with this considering they show her as a innocent girl from a small traditional village. Maybe that is also why she never went to school. Once she was labelled Bal-Vidva she was probably considered manhus (bad luck) and was kept away from society and had many privileges like school taken away from her.
What do you guys think? Any other guesses?