If you have been registered for some time and all of a sudden start seeing "You are not old enough to view this forum" when attempting to view any messages, then it is possible you left the "birthday" field blank when you registered under the old system. You will need to go to your control panel and enter your date of birth under the “Edit Profile Information†section. If this information is missing, you will not be recognized as a valid user by the system. Even if you could access everything yesterday just fine and even if you’ve been a member for years – this information MUST be filled in.
If you are undeer 18, then you are getting this error for a reason -- you really are too young. The Somn-Forum is not open to minors. If you're still curious when you're legally an adult, come back then.