"自信人生二百年，会当击水三千里"怎么翻译为英语?

Confidently believing that man can live up to two hundred years old and so can swim an accumulated length of three thousand miles. 是这样的

自信人生二百年，会当击水三千里
Confidently believing that man can live up to two hundred years old and so can swim an accumulated length of three thousand miles.