Budgie Flew to me randomly today

So today I was outside as usual watering my plants when this bird came right up to me. I gave it some water & unsalted nuts I had since I was prepared to have a bird fly to me lol. Anyway I posted every where & asked around my neighborhood if anyone is missing a bird & no claims so I got it a cage & a few necessities it would need to survive. I’m planning on keeping it & bringing it to a vet if it continues to remain unknown where owners are. Does anyone know what that gold tag might mean on its leg? And do you know if this might be a boy or girl possibly? And also how old do you think? Any tips would be great too!