Negotiating an offer, is it too late? - 8 months and counting

I want to negotiate but I am afraid they will withdraw. It has been a long 18 weeks. The hiring manager was friendly and open. Did it backfire?

If they say no, consider asking for something else, such as a review in six months.

I thanked them and said I was excited but hoped we could talk about the pay. They came back with a bit more.