I can agree with asthenia. N5 seems like an easy test, if you consider the fact that you only have to learn 100 Kanji and around 500 vocabulary words, but you are going to struggle if you can't easily read Japanese hiragana and katakana.
I would look over Tae Kim's explanations at http://www.guidetojapanese.org/blog/
of any grammar points you are having trouble with before the test.
Let us know how you do!