I studied Japanese at uni – we had five class hours a week, and I was (in theory) meant to be doing another five hours of self-study at home, but I never measured how much I was actually doing. I passed N5 after the first year, and N3 after the third, though some of my fellow students were doing N2 at the same time.

No problem. Just to add one more thing, though: I think my main reason for taking N3 over N2 is my concerns over my listening ability. If I didn’t suck so much at listening, I might have gone for N2 as well.

If you want to give things a try and see if you’re capable, they have practice questions on the JLPT webiste at http://www.jlpt.jp/e/samples/forlearners.html

Various other companies also publish unofficial study guides and practice questions, including ones that you start using at the start of the year to help you prepare for the exam at the end. You may have to look into getting those online, but if there’s a Kinokuniya anywhere near you (http://www.kinokuniya.com/), then they have a good range of Japanese books. I’m fortunate to live quite near one myself. =)