I should have received my nation insurance number 2 months ago but I still haven't?

On the 27th of November I received a letter confirming my last name, I've taken this as conformation that my national insurance number was on the way, however its a month till my 16th birthday and I still haven't received anything. I thought you'd get it 3 months before your birthday, should I be worried about it being late or is that typical.

Hi Leeruby242,
If you could call our National Insurance Helpline on 0300 200 3500 they will be able to trace your National Insurance Number and send you a letter of confirmation through the post.
Thank you.