Living abroad is such a great way to learn a language, at first it seems impossible , but because you are constantly around and it and its all you hear, you pick up on it very quickly, however if you are learning strictly based off books and a teacher, I would a say a solid 2 years of learning will do you good and have you very well off if you put a lot of effort into it. Chinese although it is easier than English there is no alphabet to write a character that's only for pinyin which doesn't help if you can' read or write a character. Every stroke must be memorized which is no easy task.