From Nookipedia, the Animal Crossing wiki
Autoconfirmed users are users who meet the following conditions:
Users are added and removed from this group automatically by the system. Users who have been autoconfirmed enjoy the following privileges:
The autoconfirmed status is not visible from the user list, but you'll know you have it when you find that you have the ability to edit semi-protected pages. Additionally, you can view a list of groups you are in on the Special:Preferences page.