Wooo- do it!!
It really depends on what you already know of the language. I'm finding it a breeze but I could already write hiragana+katakana and get the gist of simple manga.
I'm doing it through OHS and their course seems quite good, but it depends on your situation (your school having a good/bad/no teacher etc.)
In terms of 'how hard', dude, I have no idea if it's harder than other beginner courses...hard to quantify that one.