Account age and credit card history can tell a lot. If Discord can assume you were at least 7 when you first signed up for Nitro and you've been a Nitro member

Account age and credit card history can tell a lot. If Discord can assume you were at least 7 when you first signed up for Nitro and you've been a Nitro member off and on since Discord started 11 years ago, you are at least 18.