(NOTE: This response is for PlayStation users, but might help Xbox users find the answer they are looking for.)
The problem is *NOT* because the player is too young. The problem is the parental controls on your child's PSN account.
Assuming that you've properly setup your child's PSN account as a sub-account to your own (master account), all you need to do is remove the parental controls. You can do this online at https://account.sonyentertainmentnetwork.com or through your PlayStation. See guide: http://manuals.playstation.net/document/en/ps4/settings/subaccount.html
TIP: Be aware that "allow" and "off" mean a restriction is disabled (parental control is turned off), but "on" and "block" mean a restriction is enabled (parent control is turned on).
IMPORTANT: Before trying again, make sure you [1] close the game from the quick menu and [2] log your child out and then log them back in. The change may not take effect unless this is done.
I wasted over an hour on the phone with EA support. They were unable to solve the problem. I had to fix it myself by experimenting. So incredibly frustrating. I'll make sure to avoid buying EA games as much as possible. Clearly they aren't investing enough money in their support teams. In the end they asked me how I fixed it and then asked me to post my answer to their support forums. THEY WANTED ME TO DO THEIR JOB FOR THEM. 😠
