About Learning Japanese?

Hi, I'm a young teen and I'd like to know whats it's like to learn Japanese. I've been enjoying Anime/Manga and been reading tons of books, I'm very interested in Japan and their culture. So, is learing Japanese really hard if you not in Japan? (It'd be great to go, but I don't think it will happen for a while since I only came back from my last holiday (Denmark, I can speak fluent danish, since my Mum Danish) . So it'd be great to hear a few peoples opinion.