Na’vi didn’t get periods, let alone even know what they where. The other, adult, humans helped you when you got yours. You were a teenage human brought here by your parents by the RDA but then they turned to the Na’vis side later on. You became friends with Lo’ak after the scientists had set up a small living quarters at the Metkayina clan for scientists and general humans on Pandora. Lo’ak stepped into your room Hey I heard from Norm you weren’t feeling so good- woah… you okay?