The overwhelming majority of programmers likely cut their teeth on computers as kids. Any attempt to restrict computer access to 18+ will only handicap American programmers in the job market.
They require that when the administrator of the computer sets up an account for a user the admin can enter an age or birthdate for the user, and that the OS provides an interface so that apps that user runs can ask based on that admin provided information what age bracket the user is in ([0,13), [13,16), [16,18), [18,∞)).
Apps that need to make age based decisions can use that information.