Actually, I know it’s a joke, but I did forget to mention last night. The Bureau actually has strict age requirements. You must be between 25 and 35 years old. Exceptions are possible for applicants over 35 if they have some prior law enforcement background (as I recall, it specifically needs to be Federal law enforcement). You’ll sometimes see this reported as between 23 and 37. 23 is the earliest you can apply, 25 is the earliest you can be accepted. 35 is the latest you can apply, and you must be accepted before your 37th birthday.
Mandatory retirement is 55. You need to be able to serve for at least 20 years, which is why the age limit is set at 35.
No teenagers. Actually, generally speaking, no teens working for any federal agency in a law enforcement capacity. You might see some employed in a PR/outreach position, but you’re not going to be giving them badges. The only time you’ll see teenagers in law enforcement, it’ll be part of an explorer program. These are programs specifically designed to interest high school students in law enforcement careers. Think of it as the police version of ROTC. And, stating the obvious, they do not have investigation or enforcement authority.