That is more than correct even though your English sentence is in the present tense and your Japanese sentence in the past tense. We Japanese would almost never say that sentence in the present tense, so I have to say that you are correct.
Actually, 'I am chosen as the leader' is not correct in English. 'I was chosen as the leader' would be the correct way of saying it. Or 'I have been chosen.' You could also say 'I am the chosen leader,' although that has a kind of unusual sound to it--sounds like something out of a religious text.
Also, this may sound overly critical, but try to avoid saying 'we japanese' if possible. It is kind of a condescending/authoritative phrase, and creates a harsh division between speaker and listen (we and you, us and them). For example:
-We 2nd grade students would never stoop to cheating (unlike the 3rd graders who were caught recently)
-We Republicans care about teaching ethics to children (unlike those immoral Democrats)
-We Americans know how to drink our beer (unlike people from your country, you don't).
Its perhaps unfair, but I think if you are going to be talking to foreigners in Japan, avoiding this phrase is even more important. True or not, Japanese have a reputation among foreigners (particularly bitter foreigners) for strongly pitting 'us versus them.' You will unintentionally call up this stereotype whenever you say 'We Japanese,' so be careful.
Instead, use just 'we' or 'japanese.' But again, I would hesitate to say those kind of things, because again, they sound a bit authoritative/condescending. I would probably say one of the following things:
'I would almost never say...
'One would almost never say...
'You would almost never say...
They all serve approximately the same purpose, only with slightly nuances. The last one might seem a bit strange, but 'you' here means 'an English speaker in that situation,' not the person you are talking to. Looking at the three now, while they all seem natural, the third seems most fitting...
