you can pass the test anytime you want. also please note now you need KOLL. It includes life in the UK test and , and a cefr b1 level qualification. B1 level is pretty easy. you basically go and sit with an examiner for about 15 minutes, and examiner talks to you like "How are you doing?" "where do your parents live?""do you live in a house or flat?" etc etc. This is to just test that you can understand and speak basic english. you will have no difficulty passing this without any preparation.