It's the first time I have been to the US,______

It's the first time I have been to the US,______
改反意疑问句,我觉得应该是 isn't it
但答案是haven't I,
到底哪个对呢?
规则里是说要根据主句来改反意疑问句的，网上有好几个例子，把句子里的I've换成She has,后面是isn't it，这个肯定是对的，但改成I have 之后是否情况不同了呢？
大家没有明白我的意思，看下面我找到的规则：
当陈述部分是It (This,That或其他表示时间的名词+ be+the+first time(month 等)+that 从句(that 可省)时，疑问部分与主句的主语和谓语保持一致 .如：This is the third time he has left home,isn't it?Tomorrow will be the second time that I have had to have my TV set repaired again,won't it?