What was the back story of Pratha?

It seems this is big suspense in this season so they are not revealing anything about it . I feel Mahek will definitely turn negative soon as she should've been Shesh Naagin as per what they showed till now

They said that someone destroyed her home and then she was chosen instead of Mahek. So maybe it was Mahek only who destroyed her home.. But pratha doesn't know about it..?

I don't agree even with myself here. This doesn't seem probable to me at all. Must be something else lol 😆

It seems she was shesh nagin since kid but I thought she became one due to the virus