I want to know what really happened to her why didn't she mentioned about her parents, her real life @ the circle, and what trials she had to endure before she became First Enchanter. Why BioWare never give her a back story like all the other female characters?
If you notice, I addressed this in the post directly above yours.
Vivienne is guarded because the nature of the Game is such that any sign of weakness is something enemies will always seek to find. I imagine that Vivienne has spent a lot of time carefully removing or concealing any thing in her personal background that might be used by people seeking to undermine her.
She is only willing to give us vague details if we push for more information, because she simply does not trust the Inquisitor with her secrets, regardless of how much of a friend she may view them as. Even in her personal quest she does not immediately tell us what we are looking for the Wyvern heart for.
In that light, it's it's actually rather touching in that light to consider that she wanted the Inquisitor with her during the attempt to cure Bastien. We see earlier in the game that many of Bastien's friends and allies in the court are apparently unaware of his illness, so that does show a level of trust in the Inquisitor that Vivienne was willing to disclose this and be present during that moment.
I'm sure that Mary Kirby actually has a very detailed character background for Vivienne. But it would rather more fitting for us to only see the version that was left after Vivienne got a hold of it, so that large chunks of the text are now covered up and illegible.
If we were to read a biography of Vivienne, it would probably reveal such juicy details such as Vivienne's favourite song being [REDACTED] and that she used to sing it for [REDACTED] whenever she was at [REDACTED]?