Tamagotchis aren't something that you can grow out of! They're virtual pets, and there's nothing childish about that! They're like a normal pet, only pixellated. You wouldn't ever say you were too old for a dog, cat, hamster, etc. So why grow out of a Tamagotchi in this way? You shouldn't let what other people think get in the way of what you like to do. It's your life. Your choice. Enjoy it, with your Tamagotchi! :furawatchi:
Hope I help <_<