In order to change your age, you will have to change your date of birth on your Facebook account because we pull data from Facebook when creating your profile.
Once you have changed your name, follow these steps: 1. Uninstall the app (don't worry, it won't delete your account) 2. Restart your phone 3. Go to App Store or Play store 4. Install latest version of the app
Just for your reference, please review Facebook's rules on changing your date of birth and how often you can change it.