Sounds typical - adding my 21 year old provisional licence holder girlfriend to my policy cost £0.00 - and I'm a 23 year old male with a colourful history
If it's any consolation, it cost me £100 less to add my dad to my policy (3 series). I'm in my 30s, have been driving since 17, yet have no no-claims bonus as my last car was in my wife's name.