Not to try to dissuade you from learning the language, but I have a base knowledge of Japanese and the vast majority of menus and descriptions are completely incomprehensible. Games rarely have furigana (the symbols above the kanji that tell you how to read it), so until you're at a sufficiently advanced level to read a significant percentage of the 1800-ish kanji in common usage, you're going to have a tough time with any game not targeted at kids.
It's a very worthwhile endeavor, and even what little I know has enriched my enjoyment of Japanese media of all sorts, but don't expect to study for a month and understand more than a couple of the simplest menus and not a single item or ability description.
Again, I'm not trying to dissuade you. The months of effort I've put in really do feel with it. Just go in with realistic expectations or you'll just be frustrated and disappointed.