I'm not sure about JLPT N4, but definitely you can pass N5.
Usually students pass N4 after learning Japanese 1 year in university.
I recommend you to download online some samples of exam and try to pass it.
And don't forget that JLPT is not about general knowledge it's more about knowing the exam structure and prep to this exam. I know one guy who passed N1 after 1,5 year in university.
So try ;)