go to the file "playerpref" and go to the part that ays the birth date and then change it it should work
Sorry, it still doesn't work, even with the last version of Among Us. Now I can use PlayerPrefs to choose a name instead of getting a random one, but I'm still unable to sign in (errror: PlatformNotSupported while I'm on PC) and to use free chat, even if I change dates. I'll try to contact Innersloth support. Thanks for trying to help me.