YOU SAID:

if we go down, then we go down together

INTO JAPANESE

下に行けば、一緒に下に行きます

BACK INTO ENGLISH

You go downstairs, we'll go downstairs together.

INTO JAPANESE

下に行って一緒に下に行こう

BACK INTO ENGLISH

Let's go downstairs. Let's go downstairs together.

INTO JAPANESE

階下に行きましょう。一緒に下に行きましょう。

BACK INTO ENGLISH

Let's go downstairs. Let's go downstairs together.