whether or 翻译成不论是.还是.
原文的意思是,游戏对我们很流行,不论我们是老人还是年轻人.
whether可做代词
这里作为代词的whether代的是us, 换句话说前文的us和后文的whether.是同位语
not only. but also 只能这么用：
X-games is not only popular to old people but also to young people nowadays.
either... or... 词义不对了
X-games is popular to either old or young people. 指要么对老年人,要么对年轻人产生吸引.