Well, I'm 17 and I just put a battery on a Tamagotchi today I missed them so much, I had to! I don't think it matters how old you are if you love them.
I'm 11 but I've no plans to stop using Tamas when I'm 16 or older. You'll find a lot of older fans here on TamaTalk, and a lot of equally devoted younger ones as well!
I'm 17. I got my first when I was in 3rd grade (V1), and kept getting them up to the V5. This year I remembered TamaTalk and logged on, inspiring me to go out and get some batteries for my old Tamagotchis. Now I remember why I loved them so much.
I'm 23 and still love them . I had them when I was a kid, I played with them as a teenager...then a few years later I stopped playing with them... And now I'm back, lol!!