Neytiri and Sylwanin - twins?

[Fighter-of-Wars]

Sorry, but I was always under the impression that she was older than Neytiri, not younger or same age. I figured that because she was the one chosen to be with Tsu'tey and when Sylwanin was killed Neytiri was next in line.

Also she was the one that went out with the other hunters and set fire to a dozer while Neytiri was still in the school, because Sylwanin came to the school for protection and Neytiri saw her shot.

I would think that being older she would be the one being chosen to go with Tsu'tey, attacking the dozer.

Maybe I'm wrong in all of this, I don't remember where I heard that she and Tsu'tey were planned to be married or whatever (Maybe back on AF somewhere) but that was what I had thought.