which JLPT level should I take ?

I'd go for N4 if I were you- 

Even if you think you can do the N3, the success on a relatively easy test will give you a huge motivation boost, which will further your studies. If you take the N3 and happen to not pass, it may kill your motivation. For me, last year I took the N5 when I could have passed the N4, and the N5 was a piece of cake. However, it felt really good to have passed, even if it was way too easy for me. 

It's really up to you though- if you will get the same motivation boost that I did upon passing an easy test, I'd go for that one :) 

If you want to go for N3, I recommend the Shin Kanzen Master series and the Nihongo So-matome series. As well as Japanese, you need to study how to take the test. Especially the Intermediate to Advanced levels. From now until December is more than enough time to go through the books and prepare yourself well. I didn't want to take N3, so I studied my arse off for 3 months and passed N2 easily. It's all about structure in your studying.

About 5 hours a day, plus taking my grammar flashcards and Memrise with me everywhere. I studied really hard, I admit. I must have gone up a level and a half during that time. And I found that at N3 I could understand and use actual, useful Japanese. By the time I took the test I didn't even care if I failed N2 or not. By pushing myself further than I thought I could go, and seeing the improvement in my Japanese, that was the biggest confidence boost for me.

My best advice is to believe in yourself. Whatever level you decide to take. :)

I'm taking N1 (my second attempt) in a few weeks, and I'm sure I'm gonna fail. I haven't been studying hard enough. My working knowledge of Japanese is better than ever, but my test skills really suck. ^^;

Wow I hope I can pass at least N5, lol. I probably should study more. Good luck to you though with your upcoming test.

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