Well, excuse me.
Apparently I missed the part of your original post where you stated your age.
Oh, and I missed the rest of the relevant details regarding the device, when it started, whether it's ever worked, or the exact wording of the message. I only replied based on the limited amount of information I read.
Given the lack of data, I responded with the two most common causes of that kind of message. Your device is saying it's restricted from using the App Store. Child accounts and corporate accounts under an MDM (Mobile Device Management) program are the two most common causes. If neither apply to you, you'll need to provide more details in order to diagnose the cause.