Feeld is for people 18+ years of age. Real ages are shown on Feeld profiles, but not actual birth dates.
If you made a mistake on entering your date of birth, you can fix it within the first 7 days of creating an account by tapping Settings > Edit Profile > Date of birth.
After the first 7 days, you cannot change your date of birth.
If your birthdate is wrong and you need to change it, you can create a new account and delete the old one, but this has downsides. You'll lose your chats, connections, and any purchased Pings or Uplift. Consider guiding your connections to a new profile, made with a different email, before deleting your current account. Any messages you sent will disappear when you delete an account, so confirm your connections are moved before deleting.
Note: Majestic can be transferred to a new account.