YOU SAID:

if I was a jiraffe, I would have a very long neck

INTO JAPANESE

私がキリンだったら、首がとても長い

BACK INTO ENGLISH

If I was a giraffe, my neck was very long

INTO JAPANESE

キリンだったら首がとても長かった

BACK INTO ENGLISH

Giraffe had a very long neck

INTO JAPANESE

キリンは非常に長い首をしていた

BACK INTO ENGLISH

Giraffe had a very long neck