wow, I must say first "congratulations on your passion"
I can't really give you a clear answer to it, because I really don't know how well you've already learnt grammar.
Also I don't know your life style, which means I don't know how much time you can dedicate yourself to study Japanese.
Have you checked our "last minute preparation for JLPT" lessons? We have lessons focusing on JLPT, so I strongly
recommend you to try those, so that you can see "where you are" much better.