Here is the source Material:
http://powerlisting.wikia.com/wiki/Phoenix_Physiology
Phoenix's possess a form of immortality that, upon aging to death for about 500 to 1000 years, they turn to ash and restart as a baby (or a chick in this case). For the self resurrecting ability from ash that I've given her, which is also a trait derived from phoenix's, I'd say.... perhaps giving her a limit to how many times she can do that, before she comes back altogether as a child. This would make her immortal, though not without repercussion. There is also a regenerative healing factor to the Phoenix, but that's something I choose to not use for Avi.

I also took time to research modern day Egypt a little to ensure arranged marriage was still a common practice even for less than noble families, that the phoenix lore was birthed in Ancient Egypt, that that criminals that are referred to as 'bandits' still roamed the sand. Check, check, and check. ^^