If you haven't already done so you need to set up a BTID which will then allow you to access MyBT in order to see parental controls, your account info etc.
See link about BTID and how to set one up.
If you have just joined BT and have just set up MyBT today it can take a couple of days to populate it. If you still can not access it tomorrow post back.
Just to clarify, are you logging in with this link