do you think zira was born in the pridelands or do you think she was adopted into the kingdom?
No, actually, in my headcanon, Zira was from a rogue pride outside of the Pridelands known as the Outlanders, which consisted of lions and lionesses that were not of royal blood, and therefore could not live at Pride Rock nor hunt in the Pridelands. The original Outlanders consisted of several males and dozens of females that banded together and trained, day in and day out, with the goal of overthrowing the Pridelander King one day, so that they would be allowed to live within the Pridelands. Ziraās father was the unspoken leader of the Outlanders because he was the most brutal, bloodthirsty, and abusive. Though the lionesses simply wanted a better life, Ziraās father was incredibly power hungry and his goals went beyond this -- he wanted to be King himself, much like Scar.Ā
Eventually, because Ziraās father was so brutal, Zira and the rest of the lionesses banded together and overthrew him. They also drove out the remainder of the males (there were not many of them) and joined together with Zira as their new leader. Zira, unlike her father, did not want to be the Pridelander Queen, but she did idolize Scar, the Kingās brother.
Once Scar became King, he let the Outlanders into the Pridelands to give himself more leverage and more to choose from regarding heirs to his rule. There was no longer any need to fight for their right to live at Pride Rock. Zira came into the Pridelands during Scarās reign ; Nuka had already been born at that point and she was pregnant with Vitani and Kovu, and gave birth to them while living in the Pridelands. She loved and idolized Scar ; he symbolized hope and a better life for her. However, she distrusted all of the Pridelander lionesses, and they all mistrusted the Outlanders, who were obviously loyal to Scar. When Simba returned and ended up winning his throne back from Scar, Ziraās lionesses were all exiled once more for being treasonous. But in their eyes, their lives had been much better under his rule.
So longwinded answer, she was adopted momentarily into the Kingdom, but exiled once more!