Even if you do have to sign for it, it won't have anything to do with age restrictions. It depends on what kind of shipping you picked. I don't really know what Amazon's shipping options are (I just looked at them and they were site-specific terms), but usually if you order a package via EMS, you have to sign for it and they won't leave it without a signature. They'll leave a slip in your mailbox to take and pick it up, and will try to deliver it again the next day if you don't. Most other typical shipping services don't require a signature. But basically when you sign for a package it's just insurance that it got to the right people.