Removing it, the sentence is still understandable, but I feel it is more like "marry her" rather than "marry that girl" because standalone "cô" doesn't mean "girl". So, if you value strictness in translation, I would say you should not omit it.
I thought this sentence is imperative since it ends with an exlamation mark. So i used "đi" at the end, which was incorrect. Can you use that? (in the same situation/context, where you would use the english sentence)