Should I apply for my student finance now or should I wait?

Hi, I am starting a course in September 2019 and I have been told that to apply for a home student fiance it is compulsory for me to use put in my national insurance number in. I'm from Thailand and lived here in the UK for 8 years and I have dual nationality (British/ Thai) and I only have just applied for NI number about two weeks ago.I am now getting worried whether it is worth it waiting a couple of days for it to arrive to send in my application or just do it now would it make any difference? and how would it affect me since the deadline was 31st May?