cant logon to Battlefield 4 with Origen id

I'm setting up Battlefield 4 for the first time on my son's xbox360.

it will only allow me to put in my sons email address, then it tells me he's too young.

I've setup an Origen ID which seems fine, but i can't find anywhere on BF4 to logon to it.

it keeps taking me back to the email address........ AAAAAAAAgh.   Any ideas - PLEASE